JP2003028816A - Total reflection x-ray fluorescence analyzer - Google Patents
Total reflection x-ray fluorescence analyzerInfo
- Publication number
- JP2003028816A JP2003028816A JP2001218017A JP2001218017A JP2003028816A JP 2003028816 A JP2003028816 A JP 2003028816A JP 2001218017 A JP2001218017 A JP 2001218017A JP 2001218017 A JP2001218017 A JP 2001218017A JP 2003028816 A JP2003028816 A JP 2003028816A
- Authority
- JP
- Japan
- Prior art keywords
- sample
- ray
- intensity ratio
- incident angle
- raman scattering
- 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.)
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- Length-Measuring Devices Using Wave Or Particle Radiation (AREA)
- Analysing Materials By The Use Of Radiation (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、試料表面に単色化
した１次Ｘ線を微小な入射角で入射させる全反射蛍光Ｘ
線分析装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a total reflection fluorescent X for making a monochromatic primary X-ray incident on a sample surface at a minute incident angle.
The present invention relates to a line analyzer.
【０００２】[0002]
【従来の技術】従来、１次Ｘ線を試料表面に微小な入射
角で照射させる全反射蛍光Ｘ線分析装置では、バックグ
ラウンドを減少させて微弱な蛍光Ｘ線を検出できるよう
に、Ｘ線管から発生する固有Ｘ線および連続Ｘ線をその
まま照射するのではなく、分光素子で、所定の波長をも
つＸ線のみを反射して照射している。2. Description of the Related Art Conventionally, in a total reflection fluorescent X-ray analyzer for irradiating a sample surface with a primary X-ray at a small incident angle, it is necessary to reduce the background and detect weak fluorescent X-rays. Instead of directly irradiating the characteristic X-rays and continuous X-rays generated from the tube, the spectroscopic element reflects and irradiates only the X-rays having a predetermined wavelength.
【０００３】[0003]
【発明が解決しようとする課題】しかし、それでも、１
次Ｘ線の弾性散乱やラマン散乱が検出器に入射してバッ
クグラウンドとなり、微弱な蛍光Ｘ線の測定の弊害とな
ることがある。However, nonetheless, 1
The elastic scattering or Raman scattering of the next X-rays may enter the detector and become a background, which may be an obstacle to the measurement of weak fluorescent X-rays.
【０００４】これに対し、本願発明者は、弾性散乱とラ
マン散乱との強度比から、試料に関する情報、例えば、
試料表面に形成された膜の厚さが得られることを見い出
した。本発明は、このような知見に基づいてなされたも
ので、試料から発生するラマン散乱を積極的に利用し、
試料に関する情報が得られる全反射蛍光Ｘ線分析装置を
提供することを目的とする。On the other hand, the inventor of the present application, based on the intensity ratio of elastic scattering and Raman scattering, information about the sample, for example,
It was found that the thickness of the film formed on the sample surface can be obtained. The present invention has been made based on such findings, and positively utilizes Raman scattering generated from a sample,
An object of the present invention is to provide a total reflection X-ray fluorescence analyzer capable of obtaining information about a sample.
【０００５】[0005]
【課題を解決するための手段】前記目的を達成するため
に、本発明は、試料表面に単色化した１次Ｘ線を微小な
入射角で入射させ、試料から発生する２次Ｘ線の強度を
測定する全反射蛍光Ｘ線分析装置において、前記測定し
た２次Ｘ線の強度に基づいて弾性散乱とラマン散乱との
強度比を算出する強度比算出手段を備えたことを特徴と
する。In order to achieve the above object, the present invention is directed to the intensity of a secondary X-ray generated from a sample by allowing a monochromatic primary X-ray to enter the surface of the sample at a small incident angle. In the total reflection X-ray fluorescence analyzer for measuring, the intensity ratio calculating means for calculating the intensity ratio between elastic scattering and Raman scattering based on the measured intensity of the secondary X-ray is provided.
【０００６】本発明によれば、測定した２次Ｘ線の強度
に基づいて、強度比算出手段で弾性散乱とラマン散乱と
の強度比を算出するので、試料から発生するラマン散乱
を積極的に利用して試料に関する情報が得られるAccording to the present invention, the intensity ratio of the elastic scattering and the Raman scattering is calculated by the intensity ratio calculating means based on the measured intensity of the secondary X-ray, so that the Raman scattering generated from the sample is positively taken. Get information about your sample
【０００７】本発明においては、前記微小な入射角を変
化させたときの前記強度比の変化に基づいて、試料表面
に形成された膜の厚さを算出する膜厚算出手段を備える
ことが好ましい。この構成によれば、試料に関する情報
のうち、試料表面に形成された膜の厚さが求められる。In the present invention, it is preferable to include a film thickness calculating means for calculating the thickness of the film formed on the sample surface based on the change in the intensity ratio when the minute incident angle is changed. . According to this configuration, the thickness of the film formed on the sample surface is obtained from the information about the sample.
【０００８】[0008]
【発明の実施の形態】以下、本発明の一実施形態の全反
射蛍光Ｘ線分析装置を図面にしたがって説明する。ま
ず、この装置の構成について説明する。この装置は、図
１に示すように、シリコンウエハなどの試料１を載置す
る試料台１０と、Ｗ（タングステン）のターゲットから
Ｘ線２を発生するＸ線管３と、そのＸ線管３から発生す
る固有Ｘ線および連続Ｘ線２のうち、Ｘ線管３の固有Ｘ
線Ｗ−Ｍα線を反射する分光素子４と、その分光素子４
で反射されたＷ−Ｍα線（エネルギー：１．７８keV）
６、すなわち単色化された１次Ｘ線６が照射されて試料
１から発生する蛍光Ｘ線などの２次Ｘ線７の強度を測定
するＳＳＤなどの検出手段８とを備える。ここで、１次
Ｘ線６は、例えば１度以下の微小な入射角αで試料表面
１ａに入射されるが、その入射角αは、試料台１０の下
に設けられたスイベルステージなどの入射角調整手段に
より、調整される。BEST MODE FOR CARRYING OUT THE INVENTION A total reflection X-ray fluorescence analyzer according to an embodiment of the present invention will be described below with reference to the drawings. First, the configuration of this device will be described. As shown in FIG. 1, this apparatus includes a sample table 10 on which a sample 1 such as a silicon wafer is placed, an X-ray tube 3 for generating X-rays 2 from a W (tungsten) target, and the X-ray tube 3 thereof. Of the characteristic X-rays and continuous X-rays 2 generated from the X-ray tube 3
Line W-Mα line reflecting spectroscopic element 4 and its spectroscopic element 4
W-Mα rays reflected at (energy: 1.78 keV)
6, that is, a detection means 8 such as an SSD for measuring the intensity of secondary X-rays 7 such as fluorescent X-rays emitted from the sample 1 by being irradiated with the monochromatic primary X-rays 6. Here, the primary X-ray 6 is incident on the sample surface 1a at a minute incident angle α of, for example, 1 degree or less. It is adjusted by the angle adjusting means.
【０００９】また、この装置は、以下の強度比算出手段
１１および膜厚算出手段１２を含む制御手段９を備え
る。強度比算出手段１１は、測定した２次Ｘ線７の強度
に基づいて弾性散乱とラマン散乱との強度比を算出す
る。膜厚算出手段１２は、微小な入射角αを変化させた
ときの前記強度比の変化に基づいて、試料表面１ａに形
成された膜の厚さを算出する。制御手段９は、入射角調
整手段５を駆動することにより、入射角αの調整も行
う。The apparatus also comprises control means 9 including the following intensity ratio calculation means 11 and film thickness calculation means 12. The intensity ratio calculation means 11 calculates the intensity ratio between elastic scattering and Raman scattering based on the measured intensity of the secondary X-ray 7. The film thickness calculating means 12 calculates the thickness of the film formed on the sample surface 1a based on the change in the intensity ratio when the minute incident angle α is changed. The control means 9 also adjusts the incident angle α by driving the incident angle adjusting means 5.
【００１０】この装置で、glassすなわちガラス板（Ｓi
Ｏ2）およびシリコンウエハ（Ｓi）を試料１として、そ
れぞれからの２次Ｘ線７のエネルギー分布特性を測定す
ると、図２のようになる。これによると、同じＷ−Ｍα
線（エネルギー：１．７８keV）を照射しても、ＳiＯ2
からはエネルギーがそのままの弾性散乱が主として生じ
るのに対し、Ｓiからはエネルギーがやや減少したラマ
ン散乱が主として生じることが分かる。なお、Ｗ−Ｍα
線はＳiを励起しないので、どちらの試料からもＳiの蛍
光Ｘ線は生じていない。With this device, the glass or glass plate (Si
FIG. 2 shows the energy distribution characteristics of the secondary X-rays 7 from the O 1 ) and the silicon wafer (Si) as the sample 1. According to this, the same W-Mα
Even when irradiated with a line (energy: 1.78 keV), SiO 2
It can be seen from Fig. 3 that elastic scattering with the energy as it is mainly occurs, whereas from Ra, Raman scattering with slightly reduced energy mainly occurs. Note that W-Mα
Since the line does not excite Si, neither sample emits fluorescent X-rays of Si.
【００１１】次に、この装置の動作について説明する。
図１において、表面１ａにＳiＯ2の薄膜が形成されたシ
リコンウエハを試料１として、試料台１０に載置し、薄
膜の厚さを求める旨を図示しない入力手段から制御手段
９に入力すると、以下のように動作が制御される。ま
ず、入射角調整手段５により入射角αが例えば０．５度
に設定され、試料表面１ａにＷ−Ｍα線６が入射され、
発生する２次Ｘ線７の強度が検出手段８で測定され、図
３に示すように、測定値である黒丸をフィッティングし
たエネルギー分布特性が得られる。Next, the operation of this device will be described.
In FIG. 1, when a silicon wafer having a thin film of SiO 2 formed on the surface 1a is used as a sample 1 and placed on a sample table 10 and a request to obtain the thickness of the thin film is input to a control means 9 from an input means (not shown), The operation is controlled as follows. First, the incident angle adjusting means 5 sets the incident angle α to, for example, 0.5 degrees, and the W-Mα ray 6 is incident on the sample surface 1a.
The intensity of the secondary X-rays 7 generated is measured by the detecting means 8, and as shown in FIG. 3, the energy distribution characteristics obtained by fitting the black circles, which are the measured values, are obtained.
【００１２】次に、このエネルギー分布特性に基づい
て、強度比算出手段１１により、弾性散乱とラマン散乱
との強度比が算出される。すなわち、強度比算出手段１
１には、あらかじめ、Ｗ−Ｍα線の弾性散乱、ラマン散
乱それぞれの基準波形が入力されており、前記エネルギ
ー分布特性をこれらの基準波形で波形分離を行うことに
より、図３に実線、破線でそれぞれ示すように、弾性散
乱、ラマン散乱それぞれのエネルギー分布特性が測定結
果から分離される。そして、両散乱の例えばピーク強度
の比をとることにより、弾性散乱とラマン散乱との強度
比が算出される。Next, based on this energy distribution characteristic, the intensity ratio calculation means 11 calculates the intensity ratio between elastic scattering and Raman scattering. That is, the intensity ratio calculation means 1
In FIG. 1, reference waveforms of elastic scattering and Raman scattering of W-Mα rays are input in advance, and by performing waveform separation of the energy distribution characteristics with these reference waveforms, solid lines and broken lines in FIG. As shown respectively, the energy distribution characteristics of elastic scattering and Raman scattering are separated from the measurement results. Then, the intensity ratio between elastic scattering and Raman scattering is calculated by taking the ratio of the peak intensities of both scatterings, for example.
【００１３】次に、図１の入射角調整手段５により、入
射角αが、例えば０．６度、０．７度、０．８度に変更
され、各入射角αにおいて、上述したのと同様に、測定
値をフィッティングしたエネルギー分布特性、それから
分離された弾性散乱、ラマン散乱が図４〜６に示すよう
に得られ、弾性散乱とラマン散乱との強度比が算出され
る。Next, the incident angle adjusting means 5 of FIG. 1 changes the incident angle α to, for example, 0.6 degrees, 0.7 degrees, and 0.8 degrees. Similarly, the energy distribution characteristics obtained by fitting the measured values, elastic scattering and Raman scattering separated from them are obtained as shown in FIGS. 4 to 6, and the intensity ratio between elastic scattering and Raman scattering is calculated.
【００１４】さて、図３〜６のように入射角を変化させ
たときの弾性散乱、ラマン散乱の強度変化を見てみる
と、入射角が大きくなるにつれ、ラマン散乱の占める割
合が大きくなっていることが分かる。これは、図２で説
明した現象と合わせ考えると、入射角が大きくなるほ
ど、Ｗ−Ｍα線がＳiＯ2の薄膜を通過して内部のＳiで
ラマン散乱を生じる割合が大きくなるからと理解され
る。Looking at the changes in the intensity of elastic scattering and Raman scattering when the incident angle is changed as shown in FIGS. 3 to 6, the proportion of Raman scattering increases as the incident angle increases. I know that This is understood in consideration of the phenomenon described with reference to FIG. 2 because the greater the incident angle, the greater the proportion of the W-Mα ray that passes through the SiO 2 thin film and causes Raman scattering at the internal Si. .
【００１５】そこで、この装置では、図１の膜厚算出手
段１２に、あらかじめ、膜厚が既知で異なる複数の試料
１を用いて、入射角αを変化させたときの弾性散乱とラ
マン散乱との強度比の変化と、膜厚との関係を入力して
おく。そして、膜厚が未知の試料１について上述したよ
うに算出した強度比の変化を、あらかじめ入力された関
係に当てはめることにより、膜厚が算出される。このよ
うに、本実施形態の装置によれば、試料１から発生する
ラマン散乱を積極的に利用して、試料表面１ａに形成さ
れた膜の厚さが求められる。In this device, therefore, elastic scattering and Raman scattering when the incident angle α is changed by using a plurality of samples 1 whose film thicknesses are known in advance and different in film thickness calculation means 12 in FIG. The relationship between the change in the intensity ratio and the film thickness is input. Then, the film thickness is calculated by applying the change in the intensity ratio calculated as described above for the sample 1 whose film thickness is unknown to the relationship input in advance. As described above, according to the apparatus of the present embodiment, the thickness of the film formed on the sample surface 1a is obtained by positively utilizing the Raman scattering generated from the sample 1.
【００１６】この装置において、表面１ａに厚さ３００
０ÅのＳiＯ2の膜が形成されたシリコンウエハを試料１
とし、入射角αを、０．６度、０．８度、１．０度、
１．１４度に変化させたときの２次Ｘ線７のエネルギー
分布特性を図７に示す。これによると、入射角を大きく
しても、弾性散乱が主であってラマン散乱がほとんど生
じないことが分かる。これは、入射角が大きくなって
も、膜が厚いため、Ｗ−Ｍα線がＳiＯ2の薄膜を通過せ
ず、内部のＳiでラマン散乱を生じないからと理解され
る。すなわち、３０００Åの膜厚測定はこの装置の適用
外である。In this device, the surface 1a has a thickness of 300
Sample 1 is a silicon wafer on which a 0Å SiO 2 film is formed.
And the incident angle α is 0.6 degree, 0.8 degree, 1.0 degree,
FIG. 7 shows the energy distribution characteristics of the secondary X-ray 7 when changed to 1.14 degrees. From this, it can be seen that even if the incident angle is increased, elastic scattering is the main cause and Raman scattering hardly occurs. It is understood that the W-Mα ray does not pass through the thin film of SiO 2 and Raman scattering does not occur at the internal Si because the film is thick even if the incident angle becomes large. That is, the measurement of the film thickness of 3000Å is not applicable to this device.
【００１７】なお、本実施形態の装置では、試料の膜厚
を求めたが、あらかじめ強度比の変化との関係を入力し
ておけば、試料に関する他の情報、例えば、組成を求め
ることも可能である。In the apparatus of this embodiment, the film thickness of the sample was obtained, but other information about the sample, such as the composition, can be obtained if the relationship with the change in the intensity ratio is input in advance. Is.
【００１８】[0018]
【発明の効果】以上詳細に説明したように、本発明の全
反射蛍光Ｘ線分析装置によれば、測定した２次Ｘ線の強
度に基づいて、強度比算出手段で弾性散乱とラマン散乱
との強度比を算出するので、試料から発生するラマン散
乱を積極的に利用して試料に関する情報が得られる。As described above in detail, according to the total reflection X-ray fluorescence analyzer of the present invention, elastic scattering and Raman scattering are detected by the intensity ratio calculating means based on the measured secondary X-ray intensities. Since the intensity ratio of is calculated, information about the sample can be obtained by positively utilizing Raman scattering generated from the sample.
【図１】本発明の一実施形態である全反射蛍光Ｘ線装置
を示す図である。FIG. 1 is a diagram showing a total reflection fluorescent X-ray apparatus according to an embodiment of the present invention.
【図２】同装置で測定したガラス板およびシリコンウエ
ハからの２次Ｘ線のエネルギー分布特性を示す図であ
る。FIG. 2 is a diagram showing energy distribution characteristics of secondary X-rays from a glass plate and a silicon wafer measured by the same device.
【図３】同装置において入射角０．５度で測定した酸化
膜付きシリコンウエハからの２次Ｘ線のエネルギー分布
特性、それから分離された弾性散乱、ラマン散乱のエネ
ルギー分布特性を示す図である。FIG. 3 is a view showing energy distribution characteristics of secondary X-rays from a silicon wafer with an oxide film measured at an incident angle of 0.5 degree in the same apparatus, and elastic distribution and Raman scattering energy distribution characteristics separated therefrom. .
【図４】図３と同様に入射角０．６度で測定し、分離し
た各エネルギー分布特性を示す図である。FIG. 4 is a diagram showing respective energy distribution characteristics measured and separated at an incident angle of 0.6 degrees as in FIG.
【図５】図３と同様に入射角０．７度で測定し、分離し
た各エネルギー分布特性を示す図である。5 is a diagram showing energy distribution characteristics measured and separated at an incident angle of 0.7 degrees as in FIG. 3. FIG.
【図６】図３と同様に入射角０．８度で測定し、分離し
た各エネルギー分布特性を示す図である。FIG. 6 is a diagram showing energy distribution characteristics measured and separated at an incident angle of 0.8 degrees as in FIG.
【図７】同装置において入射角を変化させて測定した厚
さ３０００Åの酸化膜付きシリコンウエハからの２次Ｘ
線のエネルギー分布特性の推移を示す図である。FIG. 7: Secondary X from a 3000 Å-thick silicon wafer with an oxide film measured by changing the incident angle in the same device.
It is a figure which shows the transition of the energy distribution characteristic of a line.
１…試料、１ａ…試料表面、６…単色化した１次Ｘ線、
７…試料から発生する２次Ｘ線、１１…強度比算出手
段、１２…膜厚算出手段、α…微小な入射角。1 ... sample, 1a ... sample surface, 6 ... monochromatic primary X-ray,
7 ... Secondary X-rays generated from the sample, 11 ... Intensity ratio calculating means, 12 ... Film thickness calculating means, α ... Minute incident angle.
Claims (2)
入射角で入射させ、試料から発生する２次Ｘ線の強度を
測定する全反射蛍光Ｘ線分析装置において、 前記測定した２次Ｘ線の強度に基づいて弾性散乱とラマ
ン散乱との強度比を算出する強度比算出手段を備えたこ
とを特徴とする全反射蛍光Ｘ線分析装置。1. A total reflection fluorescent X-ray analyzer for measuring the intensity of secondary X-rays generated from a sample by injecting a monochromatic primary X-ray onto a sample surface at a small incident angle. An X-ray fluorescence analyzer for total internal reflection, comprising an intensity ratio calculating means for calculating an intensity ratio between elastic scattering and Raman scattering based on the intensity of the next X-ray.
に基づいて、試料表面に形成された膜の厚さを算出する
膜厚算出手段を備えた全反射蛍光Ｘ線分析装置。2. The film thickness calculating means according to claim 1, further comprising: a film thickness calculating unit for calculating the thickness of the film formed on the sample surface based on the change of the intensity ratio when the minute incident angle is changed. Total reflection X-ray fluorescence analyzer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001218017A JP2003028816A (en) | 2001-07-18 | 2001-07-18 | Total reflection x-ray fluorescence analyzer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001218017A JP2003028816A (en) | 2001-07-18 | 2001-07-18 | Total reflection x-ray fluorescence analyzer |
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| Publication Number | Publication Date |
|---|---|
| JP2003028816A true JP2003028816A (en) | 2003-01-29 |
Family
ID=19052254
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006053012A (en) * | 2004-08-11 | 2006-02-23 | Technos Kenkyusho:Kk | Fluorescent x-ray analyzer |
-
2001
- 2001-07-18 JP JP2001218017A patent/JP2003028816A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006053012A (en) * | 2004-08-11 | 2006-02-23 | Technos Kenkyusho:Kk | Fluorescent x-ray analyzer |
| JP4537149B2 (en) * | 2004-08-11 | 2010-09-01 | 株式会社リガク | X-ray fluorescence analysis method |
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