JPH02271212A - X-ray thickness gauge - Google Patents
X-ray thickness gaugeInfo
- Publication number
- JPH02271212A JPH02271212A JP9455489A JP9455489A JPH02271212A JP H02271212 A JPH02271212 A JP H02271212A JP 9455489 A JP9455489 A JP 9455489A JP 9455489 A JP9455489 A JP 9455489A JP H02271212 A JPH02271212 A JP H02271212A
- Authority
- JP
- Japan
- Prior art keywords
- ray
- substrate
- angle
- thin film
- total reflection
- 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
- 239000010409 thin film Substances 0.000 claims abstract description 28
- 239000000758 substrate Substances 0.000 claims abstract description 24
- 239000010408 film Substances 0.000 claims abstract description 17
- 238000000605 extraction Methods 0.000 claims description 4
- 238000010521 absorption reaction Methods 0.000 description 6
- 238000009434 installation Methods 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
Landscapes
- Length-Measuring Devices Using Wave Or Particle Radiation (AREA)
Abstract
Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は薄膜の厚さを測定するＸ線膜厚計に関する。[Detailed description of the invention] [Industrial application field] The present invention relates to an X-ray film thickness meter that measures the thickness of a thin film.
従来、この種のＸ線膜厚計はＸ線の吸収効果を利用して
金属膜の厚さを測定するもあのであり、近年、半導体基
板における薄膜の膜厚を測定するのに、よく用いられて
きた。Conventionally, this type of X-ray film thickness meter has been used to measure the thickness of metal films using the absorption effect of X-rays, and in recent years it has been frequently used to measure the thickness of thin films on semiconductor substrates. I've been exposed to it.
このｘｉ膜厚計は、図面には示さないが、被測定試料で
ある薄膜が形成された基板表面に対して所定の入射角で
Ｘ線を投射するＸ線発生器と、このＸ線発生器と対称に
斜に配置された検出器とを有している。Although not shown in the drawing, this xi film thickness meter includes an and a symmetrically and obliquely arranged detector.
この基板の薄膜の厚さを測定する場合は、まず、Ｘ線を
基板の薄膜の表面に照射し、薄膜及び基板に含まれる元
素より反射するＸ線を検出器でそれぞれ測定し、その強
度差を膜厚に換算して膜厚としていた。To measure the thickness of the thin film on this substrate, first irradiate the surface of the thin film on the substrate with X-rays, and measure the X-rays reflected from the thin film and the elements contained in the substrate with a detector. was converted into film thickness.
上述した従来のＸ線膜厚計で、例えば、１μｍ以下の厚
さの薄膜では、基板中の反射するＸ線の強度をモニタす
る場合、薄膜中の元素の密度が大きく、Ｘ線質量係数が
大きいと、薄膜中の吸収が大きくなり、１μｍ以下の薄
膜でも測定可能な場合がある。ところが、逆に、基板の
元素で反射するＸ線の強度が強く、薄膜の元素の密度が
小さく、かつ薄膜のＸ線質量吸収係数が小さいときは、
薄膜によるＸ線の吸収が小さく、膜厚測定が出来ないと
いう問題がある。For example, when using the conventional X-ray film thickness meter described above to monitor the intensity of X-rays reflected in a substrate for a thin film with a thickness of 1 μm or less, the density of elements in the thin film is large and the X-ray mass coefficient is If it is large, the absorption in the thin film becomes large, and it may be possible to measure even a thin film of 1 μm or less. However, on the other hand, when the intensity of the X-rays reflected by the elements of the substrate is strong, the density of the elements in the thin film is low, and the X-ray mass absorption coefficient of the thin film is small,
There is a problem in that the X-ray absorption by the thin film is small, making it impossible to measure the film thickness.
本発明の目的は、基板に形成された薄膜の膜厚が１μｍ
以下でも膜厚の測定が出来るＸ線膜厚計を提供すること
である。The object of the present invention is that the thickness of the thin film formed on the substrate is 1 μm.
It is an object of the present invention to provide an X-ray film thickness meter capable of measuring film thickness in the following manner.
本発明のＸ線膜厚計は、Ｘ線の全反射臨界角度θ。をも
つ基板の上に全反射臨界角度θ１をもつとともにこのθ
１が前記θ０より小さい薄膜が形成されたその膜厚を測
定するＸ線膜厚計において、Ｘ線の入射角度θｘ及び前
記基板より反射するＸ線を検知する取出し角度θ２をθ
１＜θｘ＝θ２＜θ０に設定する手段を備え構成される
。The X-ray film thickness meter of the present invention has a total reflection critical angle θ of X-rays. has a total reflection critical angle θ1 on a substrate with
In an X-ray film thickness meter that measures the thickness of a thin film formed with 1 smaller than θ0, the incident angle θx of the X-rays and the extraction angle θ2 for detecting the X-rays reflected from the substrate are θ.
1<θx=θ2<θ0.
次に、本発明について図面を参照して説明する。 Next, the present invention will be explained with reference to the drawings.
第１図は本発明の一実施例を説明するための入射、反射
Ｘ線と薄膜が形成された基板及び検出器との相対位置を
示す模式断面図である。なお、この図面では説明の都合
上屈折角については示していない。いま、第１図で示す
ように、基板３の全反射臨界角度をθ０、薄Ｍ１の全反
射臨界角度をθ１、Ｘ線の入射角度をθｘとし、この入
射Ｘ線２の入射角度θｘが、θｌ＜θｘくθ０の条件で
薄膜１に照射されると、入射Ｘ線２は薄膜１を透過し、
基板３の表面に到達する。FIG. 1 is a schematic cross-sectional view showing the relative positions of incident and reflected X-rays, a substrate on which a thin film is formed, and a detector, for explaining one embodiment of the present invention. Note that the refraction angle is not shown in this drawing for convenience of explanation. Now, as shown in FIG. 1, the critical angle of total reflection of the substrate 3 is θ0, the critical angle of total reflection of the thin M1 is θ1, and the angle of incidence of X-rays is θx, and the angle of incidence θx of the incident X-rays 2 is When the thin film 1 is irradiated under the conditions of θl<θx and θ0, the incident X-ray 2 passes through the thin film 1,
It reaches the surface of the substrate 3.
この基板３で全反射された出所Ｘ線５は、検出器４の取
り出し角度θ２がθ、くθ２くθ。のとき、最も強く検
出することが出来るという知見を得た。なお、このとき
の検出器４の取り出し角度θ２は前述のＸ線の入射角度
をθｘと等しい角度に設定しておいな。The source X-ray 5 totally reflected by this substrate 3 has an extraction angle θ2 of the detector 4, θ2×θ. We have found that the strongest detection is possible when Note that the extraction angle θ2 of the detector 4 at this time is set to be equal to the incident angle θx of the aforementioned X-rays.
ここで、例えば、薄膜１の膜さをｄとすると、入射及び
出所Ｘ線２透過距離１／２は、１＝２ｄ／ｓｉｎθ８
となる。例えば、θｘ ＝２ｍｒａｄ、ｄ＝１００人と
すると、１＝１０μｍとなる。もし、仮りに、薄膜３が
５ｉ０２であるとすると、この密度が２゜３ｇ／ｃｍ３
、）（線質量吸収係数がほぼ１００ｃｍ２／ｇであるの
で、入射Ｘ線の強度工０と検出される出所Ｘ線強度■の
比は、
Ｉ／工ｏ ＝ｅＸｐ （１００Ｘ２．３ｘｌＯ／１００
００）＝０．７９
程度となる。また、従来、行なわれていた場合では、検
出器４の取り出し角度θ２が４５°程度とすると、この
強度比Ｉ／Ｉｏが０．９９６となり、強度変化が誤差程
度になり、膜厚を評価することは難しい。これに比べ前
述の全反射を用いた本実施例では、薄膜の膜厚を評価す
るのに十分な強度減衰が得られる。Here, for example, if the thickness of the thin film 1 is d, the transmission distance 1/2 of the incident and source X-rays 2 is 1=2d/sin θ8. For example, if θx = 2 mrad and d = 100 people, then 1 = 10 μm. If the thin film 3 is 5i02, this density is 2°3g/cm3.
, ) (Since the linear mass absorption coefficient is approximately 100 cm2/g, the ratio of the incident X-ray intensity 0 and the detected source X-ray intensity
00)=0.79. In addition, in the conventional case, when the take-out angle θ2 of the detector 4 is about 45 degrees, this intensity ratio I/Io is 0.996, and the intensity change is about an error, making it difficult to evaluate the film thickness. That's difficult. In contrast, in this embodiment using total reflection described above, sufficient intensity attenuation can be obtained to evaluate the thickness of a thin film.
また、これらＸ線発生器及び検出器の取付けは、公知の
取付は手段を用い、Ｘ線防護用チャンバ外からリモート
コントロールで各々の角度を調節出来るようにすれば容
易に実現出来る。Further, the installation of the X-ray generator and the detector can be easily realized by using known installation means and by allowing the respective angles to be adjusted by remote control from outside the X-ray protection chamber.
以上説明したように本発明は、薄く、その密度が小さく
、かつ質量吸収係数の小さな薄膜の膜厚を測定する際に
、基板と薄膜のＸ線全反射臨界角度との中間の角度で、
基板の照射点に対して対称的にＸ線発生器と検出器を配
置することによって、入射Ｘ線と出所Ｘ線の強度差が大
きく得られるので、膜厚の測定を正確に測定出来るＸ線
膜厚計が得られるという効果がある。As explained above, the present invention is capable of measuring the thickness of a thin film that is thin, has a low density, and has a small mass absorption coefficient, at an angle intermediate between the critical angle of X-ray total reflection of the substrate and the thin film.
By arranging the X-ray generator and detector symmetrically with respect to the irradiation point on the substrate, a large difference in intensity between the incident and source X-rays can be obtained, making it possible to accurately measure the film thickness using X-rays. This has the effect of providing a film thickness gauge.
第１図は本発明の一実施例を説明するための入射、反射
Ｘ線と薄膜が形成された基板及び検出器との相対位置を
示す模式断面図である。
１・・・薄膜、２゛・・・入射Ｘ線、３・・・基板、４
・・・検出器、５・・・出所Ｘ線。FIG. 1 is a schematic cross-sectional view showing the relative positions of incident and reflected X-rays, a substrate on which a thin film is formed, and a detector, for explaining one embodiment of the present invention. 1... Thin film, 2゛... Incident X-ray, 3... Substrate, 4
...Detector, 5...Source X-ray.
Claims (1)
界角度θ＿１をもつとともにこのθ＿１が前記θ＿０よ
り小さい薄膜が形成されたその膜厚を測定するＸ線膜厚
計において、Ｘ線の入射角度θ＿ｘ及び前記基板より反
射するＸ線を検知する取出し角度θ＿２をθ＿１＜θ＿
ｘ＝θ＿２＜θ＿０に設定する手段を備えることを特徴
とするＸ線膜厚計In an X-ray film thickness meter that measures the thickness of a thin film formed on a substrate with a critical angle of total reflection θ_0 of X-rays, which has a critical angle of total reflection θ_1 and where θ_1 is smaller than θ_0, The incident angle θ_x and the extraction angle θ_2 for detecting the X-rays reflected from the substrate are set as θ_1<θ_
An X-ray film thickness meter characterized by comprising means for setting x=θ_2<θ_0.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9455489A JP2780324B2 (en) | 1989-04-13 | 1989-04-13 | X-ray thickness gauge |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9455489A JP2780324B2 (en) | 1989-04-13 | 1989-04-13 | X-ray thickness gauge |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02271212A true JPH02271212A (en) | 1990-11-06 |
| JP2780324B2 JP2780324B2 (en) | 1998-07-30 |
Family
ID=14113536
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9455489A Expired - Fee Related JP2780324B2 (en) | 1989-04-13 | 1989-04-13 | X-ray thickness gauge |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2780324B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2015129666A (en) * | 2014-01-07 | 2015-07-16 | 富士通株式会社 | X-ray analysis method and x-ray analysis device |
-
1989
- 1989-04-13 JP JP9455489A patent/JP2780324B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2015129666A (en) * | 2014-01-07 | 2015-07-16 | 富士通株式会社 | X-ray analysis method and x-ray analysis device |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2780324B2 (en) | 1998-07-30 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |