JPH0527835B2 - - Google Patents
Info
- Publication number
- JPH0527835B2 JPH0527835B2 JP20593284A JP20593284A JPH0527835B2 JP H0527835 B2 JPH0527835 B2 JP H0527835B2 JP 20593284 A JP20593284 A JP 20593284A JP 20593284 A JP20593284 A JP 20593284A JP H0527835 B2 JPH0527835 B2 JP H0527835B2
- Authority
- JP
- Japan
- Prior art keywords
- ion beam
- pattern
- beam diameter
- current
- detector
- 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 - Lifetime
Links
- 238000010884 ion-beam technique Methods 0.000 claims description 54
- 238000005259 measurement Methods 0.000 claims description 13
- 238000005530 etching Methods 0.000 claims description 9
- 238000000691 measurement method Methods 0.000 claims description 7
- 238000000034 method Methods 0.000 claims description 5
- 238000010586 diagram Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 4
- 238000001514 detection method Methods 0.000 description 3
- 238000011156 evaluation Methods 0.000 description 3
- 238000000605 extraction Methods 0.000 description 2
- 238000003776 cleavage reaction Methods 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 230000007017 scission Effects 0.000 description 1
- 238000000992 sputter etching Methods 0.000 description 1
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- Measurement Of Radiation (AREA)
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は集束イオンビーム装置のイオンビーム
径測定方法に関するものである。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for measuring an ion beam diameter of a focused ion beam device.
最近、集束イオンビーム装置は高輝度で微細な
ビーム径のイオン源が作られ、微細デバイスへの
応用に向けて盛んに開発研究が進められている。
Recently, ion sources with high brightness and small beam diameter have been created for focused ion beam devices, and research and development are being actively carried out with the aim of applying them to microscopic devices.
集束イオンビーム装置においては、ビーム径の
正確な測定と制御とが必要とされる。イオンビー
ム径の測定は従来イオンビームの走査照射位置に
設けたナイフエツジパターンまたは細線パターン
とイオンビーム照射位置後方の電流検出器とを用
いて行うか、あるいは上記イオンビームの走査照
射位置のパターンの近傍においた検出器を用い、
２次電子電流の変化からビーム径の評価がなされ
ていた。 Focused ion beam devices require accurate measurement and control of beam diameter. The ion beam diameter is conventionally measured using a knife edge pattern or thin line pattern provided at the scanning irradiation position of the ion beam and a current detector behind the ion beam irradiation position, or by measuring the diameter of the ion beam using a pattern at the scanning irradiation position of the ion beam. Using a nearby detector,
The beam diameter was evaluated based on changes in the secondary electron current.
第３図は集束イオンビーム装置のイオンビーム
径測定系の従来の例を示す概略図である。イオン
銃１１から引出電極１２により引き出されたイオ
ンビーム１３はレンズ１４，１５と、質量分離器
１６とで所望の集束イオンビームに制御され、こ
れを偏向器１７で走査しながら、試料ステージ１
８上に照射される。このときのイオンビーム径は
試料ステージ１８上の一部に設けた、例えばナイ
フエツジパターン１９とその下側に設けた電流検
出器２０とを用い電流検出器２０に得られたビー
ム走査による電流変化から見積ることが出来る。
あるいは、パターン１９の近傍に設けた検出器２
１を用い、検出器２１に得られた２次電子電流変
化からも同様にビーム径を見積ることも可能であ
る。 FIG. 3 is a schematic diagram showing a conventional example of an ion beam diameter measurement system for a focused ion beam device. The ion beam 13 extracted from the ion gun 11 by the extraction electrode 12 is controlled by lenses 14 and 15 and the mass separator 16 into a desired focused ion beam, and while being scanned by the deflector 17, the ion beam 13 is
8. The ion beam diameter at this time is determined by a current change due to beam scanning obtained by the current detector 20 using, for example, a knife edge pattern 19 provided on a part of the sample stage 18 and a current detector 20 provided below the knife edge pattern 19. It can be estimated from
Alternatively, the detector 2 provided near the pattern 19
1, it is also possible to estimate the beam diameter in the same way from the change in the secondary electron current obtained by the detector 21.
第４図はイオンビーム形状２２と、電流検出器
２０に得られる検出電流曲線２３との関係を模式
的に示したものである。イオンビームによるパタ
ーン１９の損傷がないものとしてビーム形状をガ
ウシヤンと仮定すると全電流Itotalの所定倍（約
12％と約88％）の電流値I1，I2に対応するビーム
走査位置変化２５がビームの半値幅２４に一致す
る。 FIG. 4 schematically shows the relationship between the ion beam shape 22 and the detected current curve 23 obtained by the current detector 20. Assuming that the pattern 19 is not damaged by the ion beam and assuming that the beam shape is Gaussian, the total current Itotal will be a predetermined times (approximately
The beam scanning position change 25 corresponding to the current values I 1 and I 2 (12% and about 88%) coincides with the half width 24 of the beam.
しかしながら、イオンビーム照射によるナイフ
エツジパターンや細線パターンのエツチング損傷
が電子ビーム照射等の場合に比べ極めて大きいこ
とが知られている。このエツチング損傷のためビ
ーム走査条件によりビーム径読取値が変化し、し
かもデータの再現性がよくないことが大きな問題
点となつており、実際にはパターン１９が模式的
に点線部２６迄エツチングされ、検出電流曲線は
２７の様にビーム走査方向に依存して曲線２３か
らずれる。すなわち、走査方向が２８ではビーム
径を小さく、逆方向では大きく見積る方向にずれ
る。この様なずれは、ビーム径の測定誤差を増す
ばかりでなく、パターン１９端が破損されるため
測定の再現性も得られないなどの問題が従来あつ
た。
However, it is known that etching damage to knife edge patterns and thin line patterns caused by ion beam irradiation is much greater than that caused by electron beam irradiation. Due to this etching damage, the beam diameter reading changes depending on the beam scanning conditions, and the reproducibility of the data is not good, which is a major problem.In reality, pattern 19 is etched schematically up to the dotted line 26. , the detected current curve deviates from the curve 23 depending on the beam scanning direction as shown in 27. That is, when the scanning direction is 28, the beam diameter is estimated to be small, and in the opposite direction, the beam diameter is estimated to be large. Such a shift not only increases the measurement error of the beam diameter, but also causes problems in that the ends of the pattern 19 are damaged, making it impossible to obtain measurement reproducibility.
本発明の目的は集束イオンビーム装置における
従来のイオンビーム径測定パターンのエツチング
損傷の問題点を改善したイオンビーム径測定方法
を提供することにある。 SUMMARY OF THE INVENTION An object of the present invention is to provide an ion beam diameter measurement method that improves the problem of etching damage in the conventional ion beam diameter measurement pattern in a focused ion beam device.
本発明はイオンビームの走査照射位置に設けた
ナイフエツジや細線等のビーム径評価パターン
と、ビーム照射位置近傍に置いた電流検出器とを
用いてイオンビーム走査による検出器電流変化か
らビーム径を見積るイオンビーム径測定方法にお
いて、前記イオンビームまたは２次電子の電流値
が所定の範囲内において、前記ナイフエツジや細
線等のビーム径評価パターンの端部をイオンビー
ム耐エツチング材料からなる遮蔽パターンでおお
うことを特徴とするイオンビーム径測定方法であ
る。
The present invention uses a beam diameter evaluation pattern such as a knife edge or thin line provided at the ion beam scanning irradiation position and a current detector placed near the beam irradiation position to estimate the beam diameter from changes in detector current due to ion beam scanning. In the ion beam diameter measuring method, the end portion of the beam diameter evaluation pattern such as the knife edge or thin line is covered with a shielding pattern made of an ion beam etching resistant material while the current value of the ion beam or secondary electrons is within a predetermined range. This is an ion beam diameter measurement method characterized by the following.
以下に本発明の実施例を説明する。 Examples of the present invention will be described below.
第１図は本発明の方法によるイオンビーム測定
系の一例を示す概略図である。本実施例では、集
束イオンビーム系は第４図と同じであるが、その
他に検出器電流の閾値セツト用レジスタ３１と、
電流比較器３２及び遮蔽パターン３３とその駆動
素子３４とを設けている。 FIG. 1 is a schematic diagram showing an example of an ion beam measurement system according to the method of the present invention. In this embodiment, the focused ion beam system is the same as that in FIG. 4, but in addition, a register 31 for setting the threshold value of the detector current,
A current comparator 32, a shielding pattern 33, and its driving element 34 are provided.
本実施例におけるイオンビーム径測定方法を第
２図ａ〜ｃに示す。すなわち、最初イオンビーム
を走査する場合、第２図ａの様にパターン１９の
端部を遮蔽パターン３３でおおわずに置き、検出
電流値が所定の閾値４１を越えた時点で第２図ｂ
の様にパターン１９の端部を遮蔽パターン３３で
カバーする。閾値４１は全電流値を予じめ測定し
ておき、これに所定の比率をかけた値を算出して
その値をレジスタ３１にセツトしておく、全電流
に対する閾値の比率はビーム形状に依存するが、
通常のイオンビーム径測定方法の様にガウシヤン
半値幅を与える約12％にとればよい。遮蔽パター
ン３３の位置制御とその駆動は電歪効果を用いた
駆動素子（圧電アクチユエータ素子）３４を用い
行なう。更に、イオンビームを走査して検出器電
流が第２の閾値４２を越えたときには第２図ｃの
様に遮蔽パターン３３を後退させ、パターン１９
の端部にビームを照射し、ビーム径評価に必要な
電流曲線を測定する。全電流に対する閾値の比率
は、ガウシヤンビーム形状の半値幅を与える値４
２より低めの値４３にセツトしておく。但し、遮
蔽パターン３３をはずした際、所望の電流値４２
が得られないことがあり得るが、その場合は遮蔽
パターン駆動系にフイードバツクしただちにパタ
ーン１９の端部をおおい、ビーム走査系とも連動
させることで所望の電流値４２近傍の電流曲線を
求める。以上の方法でビーム径２５が測定でき
る。なお、本実施例の場合、パターン１９の端部
のイオンビームエツチング損傷の程度は遮蔽パタ
ーン３３がない場合に比べ第２図ａ，ｃの斜線部
４４，４５に示す積分強度比（約24％）程度に減
少できる。また更に閾値を設け、遮蔽期間を増す
ことでイオンビームエツチング損傷を更に減少さ
せることも原理的に可能である。従つて本実施例
によりエツチング損傷によるイオンビーム径測定
の誤差や再現特性を大幅に改善できる。なお本実
施例では、ビーム径測定パターン１９としてナイ
フエツジパターンを用いたが、代わりに細線パタ
ーンあるいは種々の材料の劈開パターンを用いた
場合でも、遮蔽パターンをイオンエツチングに耐
えられる膜厚ないしは材質のもので構成すれば同
様な効果が得られる。 The ion beam diameter measurement method in this example is shown in FIGS. 2a to 2c. That is, when initially scanning the ion beam, the end of the pattern 19 is not covered with the shielding pattern 33 as shown in FIG.
The end of the pattern 19 is covered with a shielding pattern 33 as shown in FIG. For the threshold value 41, measure the total current value in advance, calculate the value by multiplying this by a predetermined ratio, and set the value in the register 31. The ratio of the threshold value to the total current value depends on the beam shape. However,
It is sufficient to set it to approximately 12%, which gives the Gaussian half-width, as in the normal ion beam diameter measurement method. The position control of the shielding pattern 33 and its driving are performed using a driving element (piezoelectric actuator element) 34 using an electrostrictive effect. Furthermore, when the ion beam is scanned and the detector current exceeds the second threshold 42, the shielding pattern 33 is retreated as shown in FIG.
A beam is irradiated to the end of the beam and the current curve necessary for beam diameter evaluation is measured. The ratio of the threshold to the total current is 4, which gives the half-width of the Gaussian beam shape.
Set it to a value of 43, which is lower than 2. However, when the shielding pattern 33 is removed, the desired current value 42
In that case, the end of the pattern 19 is covered immediately after feedback to the shielding pattern drive system, and a current curve near the desired current value 42 is obtained by interlocking with the beam scanning system. The beam diameter 25 can be measured by the above method. In the case of this embodiment, the degree of damage caused by ion beam etching at the end of the pattern 19 is approximately 24% as shown in the shaded areas 44 and 45 in FIGS. ) can be reduced to a degree. It is also theoretically possible to further reduce ion beam etching damage by further setting a threshold value and increasing the shielding period. Therefore, according to this embodiment, errors and reproducibility in ion beam diameter measurement due to etching damage can be significantly improved. In this example, a knife edge pattern was used as the beam diameter measurement pattern 19, but even if a thin line pattern or a cleavage pattern of various materials is used instead, the shielding pattern can be made with a film thickness or material that can withstand ion etching. A similar effect can be obtained by constructing it with other materials.
また本実施例では電流検出器としていわゆるフ
アラデーカツプ型の検出器２０を用いたが、代わ
りに２次電子検出器２１を用いた場合、イオンビ
ームが遮蔽パターン端により散乱される影響をさ
けるため第２図ａ，ｃでは遮蔽パターン端をイオ
ンビームで照射されない位置まで移動させる考慮
をすれば、同様に、イオンビーム径の測定が可能
である。 Further, in this embodiment, a so-called Faraday cup type detector 20 is used as the current detector, but if a secondary electron detector 21 is used instead, the second In Figures a and c, if consideration is given to moving the end of the shielding pattern to a position where it is not irradiated with the ion beam, it is possible to measure the ion beam diameter in the same way.
以上説明した様に本発明のイオンビーム径測定
方法によれば、イオンビーム径測定パターンのイ
オンビームエツチング損傷の問題を改善し、所望
のイオンビーム径の制御を実現する上で有用であ
り、集束イオンビーム装置による微細なデバイス
パターンの描画や加工の目的が達成できる効果を
有するものである。
As explained above, the ion beam diameter measurement method of the present invention is useful for improving the problem of ion beam etching damage in the ion beam diameter measurement pattern, achieving desired control of the ion beam diameter, and focusing This has the effect of achieving the purpose of drawing and processing fine device patterns using an ion beam device.
第１図は本発明の実施例の測定系を示す概略
図、第２図ａ〜ｃは本発明の実施例を説明するた
めのイオンビーム形状と検出電流との関係を示す
図、第３図は集束イオンビーム装置のイオンビー
ム径測定系の従来の例を示す概略図、第４図は従
来のイオンビーム測定法によるイオンビーム形状
の検出電流との関係を示す図である。
１１……イオン銃、１２……引出電極、１３…
…イオンビーム、１４，１５……レンズ，１６…
…質量分離器、１７……偏向器、１８……試料ス
テージ、１９……ビーム径測定パターン、２０…
…イオンビーム電流検出器、２１……２次電子検
出器、２４……半値幅ビーム径、２５……検出ビ
ーム径、２８……ビーム走査方向、３１……レジ
スタ、３２……比較器、３３……遮蔽パターン、
３４……駆動パターン、４１……第１の閾値電
流、４２……ビーム半値幅を与える電流値、４３
……第２の閾値電流、４４，４５……ビーム半値
幅の外側のビーム面積。
FIG. 1 is a schematic diagram showing a measurement system according to an embodiment of the present invention, FIGS. 2 a to c are diagrams showing the relationship between ion beam shape and detection current for explaining the embodiment of the present invention, and FIG. 3 4 is a schematic diagram showing a conventional example of an ion beam diameter measurement system of a focused ion beam device, and FIG. 4 is a diagram showing the relationship between the ion beam shape and detection current in the conventional ion beam measurement method. 11...Ion gun, 12...Extraction electrode, 13...
...Ion beam, 14, 15... Lens, 16...
... Mass separator, 17 ... Deflector, 18 ... Sample stage, 19 ... Beam diameter measurement pattern, 20 ...
... Ion beam current detector, 21 ... Secondary electron detector, 24 ... Half width beam diameter, 25 ... Detection beam diameter, 28 ... Beam scanning direction, 31 ... Register, 32 ... Comparator, 33 ...shielding pattern,
34... Drive pattern, 41... First threshold current, 42... Current value giving beam half width, 43
. . . second threshold current, 44, 45 . . . beam area outside the beam half width.
Claims (1)
エツジや細線等のビーム径測定パターンと、ビー
ム照射位置の近傍に置いた電流検出器とを用いて
イオンビーム走査による検出器電流変化からビー
ム径を見積るイオンビーム径測定方法において、
前記検出器電流の電流値が所定の範囲内におい
て、前記ナイフエツジや細線等のビーム径測定パ
ターンの端部をイオンビーム耐エツチング材料か
らなる遮蔽パターンでおおうことを特徴とするイ
オンビーム径測定方法。1. Estimating the beam diameter from changes in detector current due to ion beam scanning using a beam diameter measurement pattern such as a knife edge or thin line provided at the ion beam scanning irradiation position and a current detector placed near the beam irradiation position. In the beam diameter measurement method,
An ion beam diameter measuring method characterized in that, when the current value of the detector current is within a predetermined range, an end of the beam diameter measuring pattern such as the knife edge or thin line is covered with a shielding pattern made of an ion beam etching resistant material.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20593284A JPS6183989A (en) | 1984-10-01 | 1984-10-01 | Method for measuring diameter of ion beam |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20593284A JPS6183989A (en) | 1984-10-01 | 1984-10-01 | Method for measuring diameter of ion beam |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6183989A JPS6183989A (en) | 1986-04-28 |
| JPH0527835B2 true JPH0527835B2 (en) | 1993-04-22 |
Family
ID=16515118
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20593284A Granted JPS6183989A (en) | 1984-10-01 | 1984-10-01 | Method for measuring diameter of ion beam |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6183989A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4522267B2 (en) * | 2005-01-11 | 2010-08-11 | 日本電子株式会社 | Charged particle beam evaluation method, scanning method, and charged particle beam apparatus |
-
1984
- 1984-10-01 JP JP20593284A patent/JPS6183989A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6183989A (en) | 1986-04-28 |
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