JPH01189506A - Method for measuring thickness of film - Google Patents
Method for measuring thickness of filmInfo
- Publication number
- JPH01189506A JPH01189506A JP1342688A JP1342688A JPH01189506A JP H01189506 A JPH01189506 A JP H01189506A JP 1342688 A JP1342688 A JP 1342688A JP 1342688 A JP1342688 A JP 1342688A JP H01189506 A JPH01189506 A JP H01189506A
- Authority
- JP
- Japan
- Prior art keywords
- film
- measured
- film thickness
- thickness
- laser beam
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 19
- 230000005540 biological transmission Effects 0.000 claims description 7
- 238000005259 measurement Methods 0.000 claims description 3
- 239000010408 film Substances 0.000 description 56
- 238000000691 measurement method Methods 0.000 description 7
- 238000010586 diagram Methods 0.000 description 5
- 230000003287 optical effect Effects 0.000 description 5
- 241001422033 Thestylus Species 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000000572 ellipsometry Methods 0.000 description 2
- 239000012788 optical film Substances 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
Landscapes
- Length Measuring Devices By Optical Means (AREA)
Abstract
Description
【発明の詳細な説明】
〔概 要〕
光学的膜厚測定方法の改良に関し、
被測定膜を傷つけることなく、簡単且つ正確に数μmの
膜厚を測定することが可能な膜厚測定方法の提供を目的
とし、
被測定膜の下にレーザを透過する透過層を設け、前記被
測定膜の表面、前記透過層と前記被測定膜との境界面及
び前記透過層の前記被測定膜と接していない面の3面で
の3種の反射光束の干渉波パターンの節の位置から、前
記被測定膜の膜厚を測定するよう構成する。[Detailed Description of the Invention] [Summary] Regarding the improvement of an optical film thickness measurement method, we have developed a film thickness measurement method that can easily and accurately measure a film thickness of several μm without damaging the film to be measured. A transparent layer that transmits a laser beam is provided below the film to be measured, and the surface of the film to be measured, the interface between the transparent layer and the film to be measured, and the transparent layer in contact with the film to be measured are provided. The film thickness of the film to be measured is measured from the position of the node of the interference wave pattern of the three types of reflected light beams on the three non-contact surfaces.
本発明は、膜厚測定方法に係り、特に光学的膜厚測定方
法の改良に関するものである。The present invention relates to a film thickness measurement method, and particularly to an improvement in an optical film thickness measurement method.
膜厚測定方法は大別して光学方式と触針方式の二種類が
あるが、それぞれに種々の欠点がある。Film thickness measurement methods can be roughly divided into two types: an optical method and a stylus method, but each method has various drawbacks.
光学方式は複数の波長の入射光が必要であるか或いは、
数μmの膜厚の測定が不得手である。Optical methods require incident light of multiple wavelengths, or
It is not good at measuring film thickness of several μm.
又、触針方式は被測定膜を傷つけなければ膜厚を測定す
ることができない。Furthermore, the stylus method cannot measure the film thickness without damaging the film to be measured.
以上のような状況から被測定膜を傷つけないで容易に数
μmの膜厚を測定することが可能な膜厚測定方法が要望
されている。Under the above circumstances, there is a need for a film thickness measuring method that can easily measure a film thickness of several μm without damaging the film to be measured.
従来の膜厚測定方法には光学方式と触針方式の二種類が
ある。There are two conventional methods for measuring film thickness: an optical method and a stylus method.
光学方式には、ナノスペック式とエリプソメトリ−の二
種類があり、ナノスペック式は複数の入射光を被測定膜
に照射して膜厚を測定する方式であり、エリプソメトリ
−はμm以下の極薄膜の測定に適しているが、数μmの
膜厚の測定は不得手である。There are two types of optical methods: the nanospec method and the ellipsometry. Although it is suitable for measuring extremely thin films, it is not suitable for measuring film thicknesses of several μm.
触針方式の場合は被測定膜を傷つけなければ膜厚を測定
することができない。In the case of the stylus method, the film thickness cannot be measured without damaging the film to be measured.
以上説明の従来の膜厚測定方法で問題となるのは、光学
方式のナノスペック式は複数の波長の入射光を必要とし
、エリプソメトリ−はμm以下の極薄膜の測定に適して
いるが、数μmの膜厚の測定は不得手であり、触針方式
の場合は被測定膜を傷つけなければならないことである
。The problem with the conventional film thickness measurement methods described above is that the optical nanospec method requires incident light of multiple wavelengths, and ellipsometry is suitable for measuring extremely thin films of μm or less. Measuring a film thickness of several micrometers is inefficient, and in the case of the stylus method, the film to be measured must be damaged.
本発明は以上のような状況から被測定膜を傷っけること
なく、簡単且つ正確に数μmの膜厚を測定することが可
能な膜厚測定方法の提供を目的としたものである。The present invention aims to provide a film thickness measuring method that can easily and accurately measure a film thickness of several μm without damaging the film to be measured.
上記問題点は、被測定膜の下にレーザを透過する透過層
を設け、この被測定膜の表面、この透過層と被測定膜と
の境界面及び透過層のこの被測定膜と接していない面の
3面での3種の反射光束の干渉波パターンの節の位置か
ら、被測定膜の膜厚を測定する本発明による膜厚測定方
法によって解決される。The above problem is that a transparent layer that transmits the laser is provided below the film to be measured, and the surface of the film to be measured, the interface between the transparent layer and the film to be measured, and the transparent layer are not in contact with the film to be measured. This problem is solved by the film thickness measuring method according to the present invention, which measures the film thickness of the film to be measured from the position of the node of the interference wave pattern of the three types of reflected light beams on the three surfaces.
即ち本発明においては、被測定膜の表面にレーザを照射
し、被測定膜の下にレーザを透過する透過層を設け、こ
の被測定膜の表面、この透過層と被測定膜との境界面及
び透過層のこの被測定膜と接していない面の3面での3
種の反射光束の干渉波パターンを描かせるので、このパ
ターンの節の位置からこの被測定膜の膜厚を測定するこ
とが可能となる。That is, in the present invention, the surface of the film to be measured is irradiated with a laser, a transmission layer that transmits the laser is provided below the film to be measured, and the surface of the film to be measured and the interface between the transmission layer and the film to be measured are and 3 on the three surfaces of the transmission layer that are not in contact with this film to be measured.
Since an interference wave pattern of the reflected light beam is drawn, it is possible to measure the thickness of the film to be measured from the positions of the nodes of this pattern.
以下第1図〜第3図について本発明の一実施例を説明す
る。An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.
第1図に示すように透過層2の上に被測定膜1を置き、
集光レンズ4で集光した一定の波長のレーザビームを斜
め方向から被測定膜1の表面1aに焦点を合わせて照射
する。As shown in FIG. 1, the film to be measured 1 is placed on the transmission layer 2,
A laser beam of a constant wavelength is focused by a condensing lens 4 and is irradiated obliquely onto the surface 1a of the film to be measured 1.
この場合レーザビームは被測定膜1の表面1aと被測定
膜1と透過層2の境界面1bと透過層2の被測定膜1と
接していない反射面2aの三面でそれぞれ反射し、3種
の反射光が生じて互いに干渉することになる。In this case, the laser beam is reflected from three surfaces, namely, the surface 1a of the film to be measured 1, the interface 1b between the film to be measured 1 and the transparent layer 2, and the reflective surface 2a of the transparent layer 2 that is not in contact with the film to be measured 1. reflected light will be generated and interfere with each other.
この干渉により生じた干渉レーザビームを第1図に示す
位置に設けたCCD−array 3で受光させ、第2
図に示すような干渉パターンを描かせると、この描かれ
た干渉パターンには被測定膜lの膜厚に対応して節がで
きる。The interference laser beam generated by this interference is received by the CCD-array 3 installed at the position shown in FIG.
When an interference pattern as shown in the figure is drawn, knots are formed in the drawn interference pattern corresponding to the thickness of the film to be measured l.
第2図においては、素子間隔が14μmで、素子数が2
.048個のCCD−array 3を用いているので
、図示のように中心点をOとすると、両端は14.33
6龍と−14,336flであることを示している。In Figure 2, the element spacing is 14 μm and the number of elements is 2.
.. Since 048 CCD-array 3 is used, if the center point is O as shown in the figure, then both ends are 14.33
It shows that it is 6 dragons and -14,336 fl.
第2図に示す干渉パターンの節の位置Xと膜厚m(μm
)との関係は、近似的に次式に示す通りとなる。The position X of the node of the interference pattern shown in Fig. 2 and the film thickness m (μm
) is approximately as shown in the following equation.
従って、
ここでλ:入射光の波長
L:レンズ焦点から受光面までの距離
n1:被測定膜の屈折率
n:Q、1.2.3・・・・
を示しており、これらの常数の値は、
λ=0.78μm 、 L=90mm、 n、=2
としている。Therefore, here, λ: Wavelength of incident light L: Distance from lens focus to light receiving surface n1: Refractive index of the film to be measured n: Q, 1.2.3... These constants are The values are: λ=0.78μm, L=90mm, n,=2
It is said that
干渉パターンの節の位置Xから膜厚mを求めるには、上
記の理論式の膜厚が0〜10μmの範囲を示す第3図の
縦軸のXの値のラインとn=0或いは1,2.3・・・
の曲線との交点の横軸の値が膜厚となる。To find the film thickness m from the position 2.3...
The value on the horizontal axis at the intersection with the curve is the film thickness.
例えば、X=4の場合、mの値は、nの値に対して次の
ようになる。For example, when X=4, the value of m is as follows for the value of n.
n=0ならば m=0.70μm
n=1ならば m=2.10μm
n=2ならば m=3.49μm
n=3ならば m=4.89μm
n=4ならば m=6.29μm
n=5ならば m=7.68μm
n=6ならば m=9.08μm
nの値のどれが該当するのかは、被測定膜1の形成工程
から判断をすることが可能である。If n=0, m=0.70μm If n=1, m=2.10μm If n=2, m=3.49μm If n=3, m=4.89μm If n=4, m=6.29μm If n=5, m=7.68 μm If n=6, m=9.08 μm Which of the following values applies can be determined from the formation process of the film to be measured 1.
上記の例から明らかなように、本発明の測定レンジは1
〜50μm程度で、測定精度は0.1μm程度と考えら
れる。As is clear from the above example, the measurement range of the present invention is 1
~50 μm, and the measurement accuracy is considered to be about 0.1 μm.
なお、この測定方法に用いる入射レーザビームは集束光
でなく発散光でも支障はない。Note that the incident laser beam used in this measurement method may be a diverging light instead of a focused light without any problem.
以上の説明から明らかなように本発明によれば、極めて
簡単なレーザの被測定膜への照射により、発生する3種
の反射波の干渉波の節の位置によって、被測定膜の膜厚
測定が可能となる利点があり、著しい経済的及び、信頼
性向上の効果が期待でき工業的には極めて有用なもので
ある。As is clear from the above explanation, according to the present invention, the film thickness of the film to be measured is measured by irradiating the film to be measured with an extremely simple laser, and by determining the position of the interference wave of the three types of reflected waves generated. It has the advantage of being able to perform the following steps, and can be expected to have significant economical and reliability-improving effects, making it extremely useful industrially.
第1図は本発明による一実施例を示す模式構成図、 第2図は本発明による一実施例の干渉パターン図、 第3図は本発明による膜厚と節の位置との理論相関図、 である。 図において、 1は被測定膜、 1aは表面、 lbは境界面、 2は透過層、 2aは反射面、 3はCCD−array。 4は集光レンズ、 本発明による一実施例を示す槓式構成図第 1 図 節の位置 本発明による一実施ifl+の干渉パターン図第 27 FIG. 1 is a schematic configuration diagram showing an embodiment according to the present invention; FIG. 2 is an interference pattern diagram of an embodiment according to the present invention. Figure 3 is a theoretical correlation diagram between film thickness and node position according to the present invention; It is. In the figure, 1 is the film to be measured, 1a is the surface, lb is the boundary surface, 2 is a transparent layer, 2a is a reflective surface, 3 is a CCD-array. 4 is a condensing lens, Figure 1 is a block diagram showing an embodiment of the present invention. node position Interference pattern diagram No. 27 of one implementation of ifl+ according to the present invention
Claims (1)
設け、前記被測定膜(1)の表面(1a)、前記透過層
(2)と前記被測定膜(1)との境界面(1b)及び前
記透過層(2)の前記被測定膜(1)と接していない面
(2a)の3面での3種の反射光束の干渉波パターンの
節の位置から、前記被測定膜(1)の膜厚を測定するこ
とを特徴とする膜厚測定方法。A transmission layer (2) that transmits the laser is provided under the film to be measured (1), and the surface (1a) of the film to be measured (1), the transmission layer (2), and the film to be measured (1) are From the positions of the nodes of the interference wave patterns of the three types of reflected light beams at the boundary surface (1b) and the surface (2a) of the transmission layer (2) that is not in contact with the film to be measured (1), A film thickness measuring method characterized by measuring the film thickness of a measurement film (1).
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP1342688A JPH01189506A (en) | 1988-01-22 | 1988-01-22 | Method for measuring thickness of film |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP1342688A JPH01189506A (en) | 1988-01-22 | 1988-01-22 | Method for measuring thickness of film |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH01189506A true JPH01189506A (en) | 1989-07-28 |
Family
ID=11832811
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP1342688A Pending JPH01189506A (en) | 1988-01-22 | 1988-01-22 | Method for measuring thickness of film |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH01189506A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN105136047A (en) * | 2015-05-28 | 2015-12-09 | 清华大学深圳研究生院 | Equipment and method for measuring change in thickness of film in situ |
-
1988
- 1988-01-22 JP JP1342688A patent/JPH01189506A/en active Pending
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN105136047A (en) * | 2015-05-28 | 2015-12-09 | 清华大学深圳研究生院 | Equipment and method for measuring change in thickness of film in situ |
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