JP3777581B2 - Film thickness measurement method using X-ray diffraction method - Google Patents

Film thickness measurement method using X-ray diffraction method Download PDF

Info

Publication number
JP3777581B2
JP3777581B2 JP34130296A JP34130296A JP3777581B2 JP 3777581 B2 JP3777581 B2 JP 3777581B2 JP 34130296 A JP34130296 A JP 34130296A JP 34130296 A JP34130296 A JP 34130296A JP 3777581 B2 JP3777581 B2 JP 3777581B2
Authority
JP
Japan
Prior art keywords
thin film
diffraction line
incident angle
ray
film thickness
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.)
Expired - Fee Related
Application number
JP34130296A
Other languages
Japanese (ja)
Other versions
JPH10185537A (en
Inventor
晴男 関口
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shimadzu Corp
Original Assignee
Shimadzu Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Shimadzu Corp filed Critical Shimadzu Corp
Priority to JP34130296A priority Critical patent/JP3777581B2/en
Publication of JPH10185537A publication Critical patent/JPH10185537A/en
Application granted granted Critical
Publication of JP3777581B2 publication Critical patent/JP3777581B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Images

Landscapes

  • Length-Measuring Devices Using Wave Or Particle Radiation (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)

Description

【0001】
【発明の属する技術分野】
本発明は、試料の膜厚を測定する方法に関し、特に試料によるX線の回折強度から薄膜の膜厚を測定する膜厚測定方法に関する。
【0002】
【従来の技術】
薄膜は半導体素子や各種の機能素子等において広く使用されており、その使用の広がりと共に、該薄膜の膜厚等の品質管理や評価技術の要求も高まっている。分析装置を用いた薄膜の評価方法としては、例えば蛍光X線分析,EPMA等の元素分析,ESCA等の状態分析、X線回折法による結晶構造の解析等が知られている。
【0003】
従来、薄膜の膜厚測定では、一般に、標準試料を用いてあらかじめ検量線を求めておき、この検量線を用いた検量線法が行われており、エリプソメトリやイオンエッチングを用いたXPS測定等が知られている。
【0004】
【発明が解決しようとする課題】
従来の検量線法では、測定対象の試料と同質の膜材料の標準試料を用意し、この標準試料についてあらかじめ検量線を求める必要があり、未知試料を直接測定することができないという問題点がある。
【0005】
また、蛍光X線分析などの元素分析を用いた測定方法では、膜材料と下地に同じ元素が存在する場合には、測定精度低下するという問題点があり、エリプソメトリでは下地との界面に異種の層が形成されているときや、光学的に吸収が大きい不透明膜に対しては測定が困難であるという問題点があり、XPS測定では試料が破壊されるという問題点がある。
【0006】
そこで、本発明は前記した問題点を解決し、標準試料を必要とせず、未知試料の膜厚を直接測定することができる膜厚測定方法を提供することを目的とし、また、下地中の薄膜と同種の元素が含まれる場合でも、薄膜の膜厚の測定精度に影響しない膜厚測定方法を提供することを目的とする。
【0007】
【課題を解決するための手段】
本発明は、下地から放出されるX線の回折線の強度を、測定対象である薄膜を通して測定し、回折線の減衰の程度と薄膜の膜厚との関係を利用して、回折線の減衰傾向から薄膜の膜厚を求めるものである。
【0008】
本発明のX線回折法を用いた膜厚測定方法は、下地上に形成された薄膜の膜厚測定において、薄膜を通して下地にX線を入射し、入射角度に対する下地のX線の回折線強度を測定し、測定したX線の回折線強度を強度補正して薄膜による減衰曲線を求め、該減衰曲線からX線の回折線強度が零となる入射角度を求め、X線の入射角度と膜厚との関係を用いて求めた入射角度に対する膜厚を求めるものである。
【0009】
X線の薄膜への侵入深さは、薄膜の質量吸収係数,および密度とX線の入射角度をパラメータとする式によって表すことができ、所定の入射角で入射したX線を検出することによって、そのX線の侵入深さを知ることができる。本発明はこの関係を利用して、減衰曲線からX線の回折線強度が零となる入射角度を、上記関係式に代入して得られるX線の侵入深さを薄膜の膜厚として求めるものである。
【0010】
本発明の第1の実施形態は、測定したX線の回折線強度の強度補正は、物質に特有の回折線のピークの入射角度とピーク値の比率を用いるものであり、測定したX線の回折線強度にピーク値の比率の逆数を乗じて回折線強度の均一化を行うものである。この均一化によって得られた回折線強度のピーク値の入射角度に対する減衰傾向から減衰曲線を求め、該減衰曲線からX線の回折線強度が零となる入射角度を求める。
【0011】
本発明の第2の実施形態は、平行線束(ソーラースリット)を含む光学系を通過させたX線の回折線を検出するものであり、これによって、X線の回折線の入射角度の検出精度を向上させることができる。
【0012】
【発明の実施の形態】
以下、本発明の実施の形態を図を参照しながら詳細に説明する。
図1は薄膜のX線回折法を説明するための図であり、表面から深さxの薄層で特性X線が回折される様子を示している。図1において、入射ビームの強度をI0 (erg/cm2 /sec),その断面積を1cm2 ,試料と入射X線のなす角度をαとすると、厚みdx,長さlの薄層で回折されるX線強度dIxは試料中での吸収を受け、次式(1)で表される。
【0013】
dIx=KI0 exp{−μ(AB+BC)}dx (erg/sec) …(1)
なお、上記式において、Kは比例定数であり、μは線吸収係数である。
上記式(1)にl=1/sinα,AB=x/sinα,BC=x/sinβの関係式を代入すると、以下の式(2)が得られる。

Figure 0003777581
ディフレクトメーターではα=β=θであるから、上記式(2)は
Figure 0003777581
で表される。
【0014】
上記式(3)について、xおよび無限大の深さまで積分し、その強度比を求めると、表面から深さxまで回折されたX線強度が全回折線強度に占める割合を求めることができる。ここで、X線の侵入深さとして、無限大の厚さの試料による回折強度の99%の強度が得られる深さtを定めると、以下の式(4)で表される。
t=2.30sinθ/{(μ/ρ)ρ} …(4)
なお、(μ/ρ)は薄膜の質量吸収係数であり、ρは薄膜の密度である。
【0015】
例えば、Au薄膜をCuKαで測定するとき、回折線としてAu(111)を用いれば、回折角2θは38.2°であり、上記式(4)から侵入深さtは、t=2.30×0.327/2.14×19.32=1.8μmとなり、Auに対して1.8μmが無限大の厚さであることを示している。
また、上記式は、入射X線を試料面に対して低角入射を行なうことによってX線の侵入深さが浅くなることを示している。
本発明は、上記式(4)を用いることによって薄膜の膜厚を求めるものであり、下地と薄膜との境界における入射角を求め、この入射角を上記式(4)に代入して薄膜の膜厚を求める。
【0016】
次に、上記入射角を求める方法について、図2〜図6を用いて説明する。図2は、下地10および薄膜11に対するX線の入射角αとX線の侵入深さとの関係を表す図である。
図2において、X線を低入射角(θ1 )で薄膜20に入射させる場合には、符号21で示すように、X線の侵入深さは薄膜11内に止まり、薄膜による回折線が得られ、下地10による回折線は放出されない。これに対して、X線を高入射角(θ2 )で薄膜20に入射させる場合には、符号22で示すように、X線の侵入深さは下地10まで達し、下地10で生成された回折線は薄膜11を通過して検出される。このとき、入射するX線の強度をI0 とすると、下地10から放出された回折X線は薄膜11を通過する間に減衰して、薄膜11の外部に放出されるX線の強度はIとなる。
【0017】
前記式(4)に示したように、X線の入射角θによってX線の侵入深さを求めることができるため、図2において、X線の入射角度が薄膜11と下地10との境界面で回折したときの入射角を用いれば、薄膜11の表面から下地10の上層部までの侵入深さを求めることができ、これによって、薄膜11の膜厚を求めることができる。
【0018】
以下、図3〜図6を用いて、上記入射角度を求める方法について説明する。図3は、薄膜によるX線の回折線の強度の減衰を説明するための概略図である。図3(a)〜(c)は、下地10から強度I0 で発生したX線の回折線が、薄膜11を通過した場合を、膜厚がL1,L2,L3の順で厚くなり、それぞれ強度I1 ,I2 ,I3 で検出されることを示している。
【0019】
図3(d)は、このときの膜厚Lと検出強度Iとの関係を示すグラフであり、図中の矢印は薄膜の通過による回折線の減衰の程度を示し、薄膜の膜厚が厚いほど減衰の程度が大きくなる傾向を示している。従って、この薄膜による減衰傾向から、薄膜の膜厚を求めることができる。なお、図3(d)では、減衰の傾向を示す減衰曲線を直線で示しているが、概略を示すために便宜上直線で示したもので、実際の減衰曲線は必ずしも直線的に変化するものではない。
【0020】
ここで、薄膜11を通過した回折線の強度を検出する場合には、上記図3中の下地で発生するX線の回折線の強度I0 を、直接求めることは困難である。そのため、本発明では、測定したX線の回折線強度を強度補正して薄膜による減衰曲線を求める。この回折線強度の強度補正は、物質に特有の回折線のピークの入射角度とピーク値の比率を用いるものであり、測定したX線の回折線強度にピーク値の比率の逆数を乗じて回折線強度の均一化を行うものである。
【0021】
以下、上記減衰曲線について図4,5,6を用いて説明する。図4は下地10のみで薄膜11が存在しない場合について、入射角θに対するX線の回折線の状態を示した図である。X線a,b,cが下地10に対して入射角θa,θb,θcで順に低入射角から高入射角で図4(a)に示すように入射して回折されると、このとき検出される回折線の強度は、図4(b)中の回折線強度Ia,Ib,Icとなる。この回折線強度の絶対値は、入射するX線の強度や検出器の感度等の測定条件で異なるため、この検出値から回折線の減衰の状態を求めることはできない。そこで、本発明では、下地に含まれる物質に特有の回折線強度のピーク値の比率IA ,IB ,IC を用い、このピーク値の比率の逆数を検出した回折線強度Ia,Ib,Icに乗じることによって、回折線強度の補正して回折線強度の均一化を行う。なお、物質に特有の回折線強度のピーク値は、例えばJCPDSカード情報から得ることができる。
【0022】
図4(c)は補正後の回折線強度を示しており、薄膜を通過することによる回折線の減衰が無い場合には、図に示すように等しいレベルとなる。
【0023】
これに対して、図5,6は下地10上に薄膜11が存在する場合について、入射角θに対するX線の回折線の状態を示しており、図5は膜厚が薄い場合を示し、図6の膜厚が厚い場合を示している。
【0024】
図5(a)は、前記図4と同様に下地に対して入射角θa,θb,θcで入射した場合を示し、このときに検出される回折線強度Ia1,Ib1,Ic1は薄膜を通過することによって減衰する。なお、図5(b)中に示す破線は減衰が無い場合の回折線強度Ia,Ib,Icを示している。
【0025】
図5(c)は、図4(c)と同様に、下地に含まれる物質に特有の回折線強度のピーク値の比率IA ,IB ,IC を用い、このピーク値の比率の逆数を検出した回折線強度Ia1,Ib1,Ic1に乗じて回折線強度を補正した状態を示している。図5(c)の補正後の回折線強度において、減衰が無い場合のレベル(図中の一点鎖線)からの差da1,db1,dc1は、薄膜による減衰の程度を表しており、回折線強度のピークを結ぶことによって減衰曲線(図中の破線)を形成することができる。
【0026】
この減衰曲線を延長して横軸と交差する入射角を求めると、強度零のときの入射角度θαを得ることができる。このときの入射角度θαは、図5(a)において、入射したX線が薄膜11の底面(下地10の最上層面)で回折したときの角度であり、この角度は薄膜11の膜厚を表すパラメータとなっている。
【0027】
従って、この減衰曲線から求めた入射角度θαを、前記式(4)に代入することによって、薄膜の膜厚を求めることができる。なお、このとき、式(4)には薄膜の質量吸収係数(μ/ρ)および薄膜の密度ρを求めて代入する。
【0028】
図6は膜厚が厚い場合であり、図5と同様の処理によって、図6(c)に示す減衰曲線を求め、この減衰曲線を延長して横軸と交差する入射角から強度零のときの入射角度θβを得、さらに、この入射角度θβを前記式(4)に代入することによって、薄膜の膜厚を求める。
【0029】
次に、本発明のX線回折法を用いた膜厚測定方法を適用するX線回折装置の概略について、図7を用いて説明する。X線回折装置は、X線源1から発したX線を一次側スリット2を通して試料3に入射し、試料3で回折した回折線を二次側スリット4を通して平行結晶5に入射して分光させて、検出器6に入射する。検出器6は、試料3に対するX線の入射角を変更しながら回折線強度を検出する。
【0030】
二次側スリット4として、平行線束(ソーラースリット)を含む光学系によって形成することができ、これによって、入射角の精度を向上させて、ノイズ分の除去を行うことができる。
【0031】
【発明の効果】
以上説明したように、本発明のX線回折法を用いた膜厚測定方法によれば、標準試料を必要とせず、未知試料の膜厚を直接測定することができ、また、下地中の薄膜と同種の元素が含まれる場合でも、薄膜の膜厚の測定精度の低下を防止することができる。
【図面の簡単な説明】
【図1】薄膜のX線回折法を説明するための図である。
【図2】下地および薄膜に対するX線の入射角とX線の侵入深さとの関係を表す図である。
【図3】薄膜によるX線の回折線の強度の減衰を説明するための概略図である。
【図4】下地で薄膜が存在しない場合の入射角に対するX線の回折線の状態を示した図である。
【図5】下地上に薄い薄膜が存在する場合の入射角に対するX線の回折線の状態を示した図である。
【図6】下地上に厚い薄膜が存在する場合の入射角に対するX線の回折線の状態を示した図である。
【図7】本発明のX線回折法を用いた膜厚測定方法を適用するX線回折装置の概略図である。
【符号の説明】
1…X線源、2,4…スリット、3…試料、5…平行結晶、6…検出器、10…下地、11,12,13…薄膜。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for measuring the film thickness of a sample, and more particularly to a film thickness measuring method for measuring the film thickness of a thin film from the X-ray diffraction intensity of the sample.
[0002]
[Prior art]
Thin films are widely used in semiconductor elements, various functional elements, and the like, and with the spread of their use, there is an increasing demand for quality control and evaluation techniques such as film thickness of the thin films. As a thin film evaluation method using an analyzer, for example, fluorescent X-ray analysis, elemental analysis such as EPMA, state analysis such as ESCA, analysis of crystal structure by X-ray diffraction method, and the like are known.
[0003]
Conventionally, in measuring the film thickness of a thin film, a calibration curve is generally obtained in advance using a standard sample, and a calibration curve method using this calibration curve is performed, such as XPS measurement using ellipsometry or ion etching, etc. It has been known.
[0004]
[Problems to be solved by the invention]
In the conventional calibration curve method, it is necessary to prepare a standard sample of a film material of the same quality as the sample to be measured, and to obtain a calibration curve in advance for this standard sample, which makes it impossible to directly measure unknown samples. .
[0005]
In addition, a measurement method using elemental analysis such as X-ray fluorescence analysis has a problem that the measurement accuracy is lowered when the same element exists in the film material and the base, and in ellipsometry, there is a problem at the interface with the base. There is a problem that the measurement is difficult when an opaque film having a large optical absorption is formed or an opaque film having a large optical absorption, and the sample is destroyed in the XPS measurement.
[0006]
Accordingly, the present invention has an object to provide a film thickness measuring method that solves the above-described problems and that can directly measure the film thickness of an unknown sample without requiring a standard sample. It is an object to provide a film thickness measurement method that does not affect the measurement accuracy of the film thickness of a thin film even when the same kind of element is included.
[0007]
[Means for Solving the Problems]
The present invention measures the intensity of the X-ray diffraction line emitted from the substrate through the thin film to be measured, and uses the relationship between the degree of attenuation of the diffraction line and the film thickness of the thin film to attenuate the diffraction line. The film thickness of the thin film is obtained from the tendency.
[0008]
In the film thickness measurement method using the X-ray diffraction method of the present invention, in the film thickness measurement of a thin film formed on the base, X-rays are incident on the base through the thin film, and the X-ray diffraction line intensity of the base with respect to the incident angle The X-ray diffraction line intensity is corrected to obtain an attenuation curve by the thin film, and an incident angle at which the X-ray diffraction line intensity becomes zero is obtained from the attenuation curve. The film thickness with respect to the incident angle obtained using the relationship with the thickness is obtained.
[0009]
The penetration depth of the X-ray into the thin film can be expressed by an equation using the thin film mass absorption coefficient and the density and the incident angle of the X-ray as parameters, and by detecting the X-ray incident at a predetermined incident angle. The penetration depth of the X-ray can be known. The present invention uses this relationship to obtain the X-ray penetration depth obtained by substituting the incident angle at which the X-ray diffraction line intensity becomes zero from the attenuation curve into the above relational expression as the film thickness of the thin film. It is.
[0010]
In the first embodiment of the present invention, the intensity correction of the measured X-ray diffraction line intensity uses the ratio of the incident angle of the peak of the diffraction line peculiar to the substance and the peak value. The diffraction line intensity is made uniform by multiplying the diffraction line intensity by the reciprocal of the peak value ratio. An attenuation curve is obtained from the attenuation tendency with respect to the incident angle of the peak value of the diffraction line intensity obtained by this homogenization, and an incident angle at which the X-ray diffraction line intensity becomes zero is obtained from the attenuation curve.
[0011]
The second embodiment of the present invention detects an X-ray diffraction line that has passed through an optical system including a parallel beam bundle (solar slit), and thereby detects the incident angle of the X-ray diffraction line. Can be improved.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram for explaining an X-ray diffraction method of a thin film, and shows how characteristic X-rays are diffracted by a thin layer having a depth x from the surface. In FIG. 1, when the intensity of the incident beam is I 0 (erg / cm 2 / sec), its cross-sectional area is 1 cm 2 , and the angle formed by the sample and the incident X-ray is α, a thin layer having a thickness dx and a length l is obtained. The diffracted X-ray intensity dIx receives absorption in the sample and is expressed by the following formula (1).
[0013]
dIx = KI 0 exp {−μ (AB + BC)} dx (erg / sec) (1)
In the above formula, K is a proportional constant, and μ is a linear absorption coefficient.
Substituting the relational expression of l = 1 / sin α, AB = x / sin α, BC = x / sin β into the above equation (1), the following equation (2) is obtained.
Figure 0003777581
Since α = β = θ in the deflectometer, the above equation (2) is
Figure 0003777581
It is represented by
[0014]
About the said Formula (3), if it integrates to x and infinite depth, and the intensity ratio is calculated | required, the ratio for which the X-ray intensity diffracted from the surface to the depth x accounts to the total diffraction line intensity can be calculated | required. Here, when the depth t at which 99% of the diffraction intensity by the sample of infinite thickness is obtained is determined as the penetration depth of the X-ray, it is expressed by the following formula (4).
t = 2.30 sin θ / {(μ / ρ) ρ} (4)
Note that (μ / ρ) is the mass absorption coefficient of the thin film, and ρ is the density of the thin film.
[0015]
For example, when Au (111) is used as a diffraction line when measuring an Au thin film with CuKα, the diffraction angle 2θ is 38.2 °, and the penetration depth t is t = 2.30 from the above equation (4). × 0.327 / 2.14 × 19.32 = 1.8 μm, indicating that 1.8 μm is an infinite thickness with respect to Au.
Further, the above formula shows that the penetration depth of X-rays becomes shallow by making incident X-rays incident at a low angle on the sample surface.
In the present invention, the film thickness of the thin film is obtained by using the above formula (4). The incident angle at the boundary between the base and the thin film is obtained, and this incident angle is substituted into the above formula (4) to obtain the film thickness. Find the film thickness.
[0016]
Next, a method for obtaining the incident angle will be described with reference to FIGS. FIG. 2 is a diagram illustrating the relationship between the X-ray incident angle α and the X-ray penetration depth with respect to the base 10 and the thin film 11.
In FIG. 2, when X-rays are incident on the thin film 20 at a low incident angle (θ1), the penetration depth of the X-rays stops in the thin film 11 as shown by reference numeral 21, and diffraction lines by the thin film are obtained. The diffraction lines due to the base 10 are not emitted. On the other hand, when X-rays are made incident on the thin film 20 at a high incident angle (θ2), the penetration depth of the X-rays reaches the base 10 as shown by reference numeral 22, and the diffraction generated by the base 10 The line is detected through the thin film 11. At this time, if the intensity of the incident X-ray is I0, the diffracted X-ray emitted from the base 10 is attenuated while passing through the thin film 11, and the intensity of the X-ray emitted to the outside of the thin film 11 is I. Become.
[0017]
As shown in the equation (4), since the X-ray penetration depth can be obtained from the X-ray incident angle θ, the X-ray incident angle is the boundary surface between the thin film 11 and the substrate 10 in FIG. Can be used to determine the penetration depth from the surface of the thin film 11 to the upper layer portion of the base 10, and thereby the film thickness of the thin film 11 can be determined.
[0018]
Hereinafter, the method for obtaining the incident angle will be described with reference to FIGS. FIG. 3 is a schematic diagram for explaining the attenuation of the intensity of X-ray diffraction lines by a thin film. 3 (a) to 3 (c) show the case where the X-ray diffraction line generated from the base 10 with the intensity I0 passes through the thin film 11, and the film thickness increases in the order of L1, L2, and L3. It is detected by I1, I2, and I3.
[0019]
FIG. 3D is a graph showing the relationship between the film thickness L and the detection intensity I at this time, and the arrows in the figure indicate the degree of attenuation of diffraction lines due to the passage of the thin film, and the thin film is thick. The degree of attenuation tends to increase. Therefore, the film thickness of the thin film can be obtained from the attenuation tendency by the thin film. In FIG. 3D, the attenuation curve indicating the tendency of attenuation is shown by a straight line. However, for the sake of simplicity, the attenuation curve is shown by a straight line for convenience, and the actual attenuation curve does not necessarily change linearly. Absent.
[0020]
Here, when detecting the intensity of the diffraction line that has passed through the thin film 11, it is difficult to directly determine the intensity I0 of the X-ray diffraction line generated at the base in FIG. Therefore, in the present invention, the attenuation curve of the thin film is obtained by correcting the intensity of the measured X-ray diffraction line. The intensity correction of the diffraction line intensity uses the ratio of the incident angle of the peak of the diffraction line peculiar to the substance and the peak value, and multiplies the measured X-ray diffraction line intensity by the reciprocal of the ratio of the peak value. The line intensity is made uniform.
[0021]
Hereinafter, the attenuation curve will be described with reference to FIGS. FIG. 4 is a diagram showing a state of an X-ray diffraction line with respect to the incident angle θ when only the base 10 is not present and the thin film 11 is not present. When X-rays a, b, and c are incident and diffracted with respect to the base 10 in order of incidence angles θa, θb, and θc from a low incidence angle to a high incidence angle as shown in FIG. The intensity of the diffraction lines to be obtained is the diffraction line intensities Ia, Ib, and Ic in FIG. Since the absolute value of the diffraction line intensity varies depending on measurement conditions such as the intensity of incident X-rays and the sensitivity of the detector, the state of attenuation of the diffraction line cannot be obtained from the detected value. Therefore, in the present invention, the ratios IA, IB, and IC of the peak values of the diffraction line intensity peculiar to the substance contained in the base are used, and the reciprocal numbers of the peak value ratios are multiplied by the detected diffraction line intensities Ia, Ib, and Ic. Thus, the diffraction line intensity is corrected to make the diffraction line intensity uniform. In addition, the peak value of the diffraction line intensity peculiar to a substance can be obtained from JCPDS card information, for example.
[0022]
FIG. 4C shows the corrected diffraction line intensity, and when there is no attenuation of the diffraction line due to passing through the thin film, the levels are equal as shown in the figure.
[0023]
On the other hand, FIGS. 5 and 6 show the state of the X-ray diffraction line with respect to the incident angle θ when the thin film 11 is present on the base 10, and FIG. 5 shows the case where the film thickness is thin. 6 shows a case where the film thickness is thick.
[0024]
FIG. 5 (a) shows the case where the incident light is incident on the substrate at the incident angles θa, θb, θc as in FIG. 4, and the diffraction line intensities Ia1, Ib1, Ic1 detected at this time pass through the thin film. It attenuates by. In addition, the broken line shown in FIG.5 (b) has shown diffraction line intensity Ia, Ib, Ic when there is no attenuation.
[0025]
In FIG. 5 (c), as in FIG. 4 (c), the ratios IA, IB, and IC of the peak values of the diffraction line intensity peculiar to the substance contained in the base were used, and the reciprocal of this peak value ratio was detected. The diffraction line intensities Ia1, Ib1, and Ic1 are multiplied to correct the diffraction line intensity. In the corrected diffraction line intensity in FIG. 5C, the differences da1, db1, and dc1 from the level where there is no attenuation (dashed line in the figure) represent the degree of attenuation by the thin film, and the diffraction line intensity. An attenuation curve (broken line in the figure) can be formed by connecting the peaks.
[0026]
When the incident angle intersecting the horizontal axis is obtained by extending this attenuation curve, the incident angle θα when the intensity is zero can be obtained. The incident angle θα at this time is an angle when the incident X-ray is diffracted at the bottom surface of the thin film 11 (the uppermost layer surface of the base 10) in FIG. 5A, and this angle represents the film thickness of the thin film 11. It is a parameter.
[0027]
Therefore, the thickness of the thin film can be obtained by substituting the incident angle θα obtained from this attenuation curve into the equation (4). At this time, the mass absorption coefficient (μ / ρ) of the thin film and the density ρ of the thin film are obtained and substituted into Equation (4).
[0028]
FIG. 6 shows a case where the film thickness is large. When the attenuation curve shown in FIG. 6C is obtained by the same processing as in FIG. 5, the attenuation curve is extended and the intensity is zero from the incident angle intersecting the horizontal axis. Is obtained, and the incident angle θβ is substituted into the equation (4) to obtain the film thickness of the thin film.
[0029]
Next, an outline of an X-ray diffraction apparatus to which the film thickness measurement method using the X-ray diffraction method of the present invention is applied will be described with reference to FIG. The X-ray diffractometer makes X-rays emitted from the X-ray source 1 enter the sample 3 through the primary side slit 2, and the diffraction lines diffracted by the sample 3 enter the parallel crystal 5 through the secondary side slit 4 to be dispersed. Then, the light enters the detector 6. The detector 6 detects the diffraction line intensity while changing the incident angle of the X-ray with respect to the sample 3.
[0030]
The secondary slit 4 can be formed by an optical system including a parallel line bundle (solar slit), thereby improving the accuracy of the incident angle and removing noise.
[0031]
【The invention's effect】
As described above, according to the film thickness measuring method using the X-ray diffraction method of the present invention, it is possible to directly measure the film thickness of an unknown sample without requiring a standard sample, Even when the same kind of element is included, it is possible to prevent a decrease in the measurement accuracy of the film thickness of the thin film.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining an X-ray diffraction method of a thin film.
FIG. 2 is a diagram illustrating a relationship between an X-ray incident angle and an X-ray penetration depth with respect to a base and a thin film.
FIG. 3 is a schematic diagram for explaining the attenuation of the intensity of an X-ray diffraction line by a thin film.
FIG. 4 is a diagram showing a state of an X-ray diffraction line with respect to an incident angle when a thin film is not present on the base.
FIG. 5 is a diagram showing a state of an X-ray diffraction line with respect to an incident angle when a thin thin film is present on a base.
FIG. 6 is a diagram showing a state of an X-ray diffraction line with respect to an incident angle when a thick thin film is present on a base.
FIG. 7 is a schematic view of an X-ray diffraction apparatus to which a film thickness measurement method using the X-ray diffraction method of the present invention is applied.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... X-ray source, 2, 4 ... Slit, 3 ... Sample, 5 ... Parallel crystal, 6 ... Detector, 10 ... Base | substrate, 11, 12, 13 ... Thin film.

Claims (1)

下地上に形成した薄膜の膜厚測定において、薄膜を通して下地にX線を照射し、入射角度に対する下地のX線の回折線強度を測定し、測定したX線の回折線強度に下地に含まれる物質に特有のピーク値の比率の逆数を乗じて回折線強度を均一化し、均一化した回折線強度のピーク値の入射角度に対する減衰傾向から薄膜による減衰曲線を求め、該減衰曲線からX線の回折線強度が零となる入射角度を求め、X線の入射角度と膜厚との関係を用いて求めた入射角度に対する膜厚を求めることを特徴とするX線回折法を用いた膜厚測定方法。  When measuring the thickness of a thin film formed on the ground, the base is irradiated with X-rays, the X-ray diffraction line intensity of the base with respect to the incident angle is measured, and the measured X-ray diffraction line intensity is included in the base The diffraction line intensity is made uniform by multiplying the reciprocal of the ratio of the peak value peculiar to the substance, the attenuation curve by the thin film is obtained from the attenuation tendency with respect to the incident angle of the peak value of the uniform diffraction line intensity, Film thickness measurement using an X-ray diffraction method characterized in that the incident angle at which the diffraction line intensity becomes zero is obtained, and the film thickness is obtained with respect to the incident angle obtained using the relationship between the X-ray incident angle and the film thickness. Method.
JP34130296A 1996-12-20 1996-12-20 Film thickness measurement method using X-ray diffraction method Expired - Fee Related JP3777581B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP34130296A JP3777581B2 (en) 1996-12-20 1996-12-20 Film thickness measurement method using X-ray diffraction method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP34130296A JP3777581B2 (en) 1996-12-20 1996-12-20 Film thickness measurement method using X-ray diffraction method

Publications (2)

Publication Number Publication Date
JPH10185537A JPH10185537A (en) 1998-07-14
JP3777581B2 true JP3777581B2 (en) 2006-05-24

Family

ID=18345006

Family Applications (1)

Application Number Title Priority Date Filing Date
JP34130296A Expired - Fee Related JP3777581B2 (en) 1996-12-20 1996-12-20 Film thickness measurement method using X-ray diffraction method

Country Status (1)

Country Link
JP (1) JP3777581B2 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2934372B1 (en) * 2008-07-22 2010-09-03 Commissariat Energie Atomique METHOD FOR OBTAINING THE STRUCTURAL FACTOR OF AN AMORPHOUS MATERIAL, IN PARTICULAR AN AMORPHOUS GLASS

Also Published As

Publication number Publication date
JPH10185537A (en) 1998-07-14

Similar Documents

Publication Publication Date Title
JP4262734B2 (en) X-ray fluorescence analyzer and method
US7885383B1 (en) Method for measuring crystallite size with a two-dimensional X-ray diffractometer
JPS5825976B2 (en) Device for quantifying at least one element in a medium using electromagnetic radiation method
JP3777581B2 (en) Film thickness measurement method using X-ray diffraction method
CA1160364A (en) Device for determining the proportions by volume of a multiple-component mixture by irradiation with several gamma lines
JP3529065B2 (en) X-ray small angle scattering device
JPS63121737A (en) Method and device for measuring analytic depth in layer near surface in total reflection range
JP2016176931A (en) Quantitative X-ray analysis and ratio correction method
JP2006313132A (en) Sample analyzing method and x-ray analyzing system
JPH0915392A (en) X-ray analyzer
JP3034420B2 (en) Background correction method for X-ray fluorescence analysis
JP3000892B2 (en) Film thickness measurement method using X-ray diffraction
JP2906606B2 (en) Qualitative analysis of thin film samples
JP2961881B2 (en) X-ray diffraction method for measuring film thickness
JP2912127B2 (en) X-ray fluorescence analysis method
JPH0833359B2 (en) Total reflection X-ray fluorescence analyzer
JP3333940B2 (en) Apparatus and method for calibrating apparatus for measuring layer thickness using X-rays
JP3047563B2 (en) X-ray diffraction method for measuring film thickness
JPH04198745A (en) X-ray diffracting method
JP4677606B2 (en) X-ray fluorescence analysis
JPH11248653A (en) Method and device for analyzing total reflection fluorescent x-ray
JP2681974B2 (en) X-ray surface stress measuring device
JP2780324B2 (en) X-ray thickness gauge
JPH02107952A (en) X-ray diffraction measurement for powder
SU777563A1 (en) Method of measuring the content of fillers in paper web

Legal Events

Date Code Title Description
A977 Report on retrieval

Free format text: JAPANESE INTERMEDIATE CODE: A971007

Effective date: 20050921

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20051121

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20060117

TRDD Decision of grant or rejection written
A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20060206

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20060219

R150 Certificate of patent or registration of utility model

Free format text: JAPANESE INTERMEDIATE CODE: R150

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20100310

Year of fee payment: 4

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20100310

Year of fee payment: 4

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20110310

Year of fee payment: 5

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20110310

Year of fee payment: 5

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20120310

Year of fee payment: 6

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20120310

Year of fee payment: 6

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20130310

Year of fee payment: 7

FPAY Renewal fee payment (event date is renewal date of database)

Free format text: PAYMENT UNTIL: 20140310

Year of fee payment: 8

LAPS Cancellation because of no payment of annual fees