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JPS6297246A - Scanning type electron microscope - Google Patents

Scanning type electron microscope

Info

Publication number
JPS6297246A
JPS6297246A JP60238833A JP23883385A JPS6297246A JP S6297246 A JPS6297246 A JP S6297246A JP 60238833 A JP60238833 A JP 60238833A JP 23883385 A JP23883385 A JP 23883385A JP S6297246 A JPS6297246 A JP S6297246A
Authority
JP
Japan
Prior art keywords
electrode
sample
electron beam
secondary electrons
electron microscope
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
Application number
JP60238833A
Other languages
Japanese (ja)
Inventor
Hiroaki Morimoto
森本 博明
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.)
Mitsubishi Electric Corp
Original Assignee
Mitsubishi Electric 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 Mitsubishi Electric Corp filed Critical Mitsubishi Electric Corp
Priority to JP60238833A priority Critical patent/JPS6297246A/en
Publication of JPS6297246A publication Critical patent/JPS6297246A/en
Pending legal-status Critical Current

Links

Abstract

PURPOSE:To enable the detection of secondary electrons produced in a deep groove of sample by arranging a first electrode for taking out secondary electrons between an objective lens and the surface of the sample while a secondary electrode between the first electrode and an electron beam path. CONSTITUTION:A preliminary electrode 16 for taking out secondary electrons 15 is arranged between an onjective lens 24 and the surface of a sample 33 in a scanning type electron microscope while a shield electrode 17 is arranged between the preliminary electrode 16 and an electron beam path 22. The preliminary electrode 16 is maintained at positive potential against the sample 33 while the shield electrode 17 is set to the ground potential. Secondary electrons 15 produced at the bottom 34 of a narrow and deep groove 36 formed in the surface of the sample 33 are taken out from the groove 36 to arrive to a detector 28. The shield electrode 17 will prevent bad influence of the preliminary electrode 16 onto the path of the electron beam 22. Consequently, the deep groove section of sample can be observed easily and reliably.

Description

【発明の詳細な説明】 この発明は、走査型電子顕微鏡、特に半導体集積回路素
子等の表面の微細形状を観測するための走査型電子顕微
鏡に関する。
DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a scanning electron microscope, and particularly to a scanning electron microscope for observing minute shapes on the surface of a semiconductor integrated circuit element or the like.

[従来の技術] 近年の半導体集積回路技術の進歩に伴なって、半導体回
路素子サイズが微細化され、回路素子の大きさは1μl
またはそれ以下のものが実用化されてきている。このよ
うな微細な回路素子の検査や観測には、光学的な顕微鏡
に代わって解像度の良い走査型電子顕微鏡が用いられる
ようになってきている。
[Prior art] With the recent progress in semiconductor integrated circuit technology, the size of semiconductor circuit elements has been miniaturized, and the size of circuit elements has decreased to 1 μl.
Or something less than that has been put into practical use. For inspection and observation of such minute circuit elements, scanning electron microscopes with high resolution have come to be used instead of optical microscopes.

第2図は上述のような目的に用いられる走査型電子顕微
鏡の原理を示すための図である。第2図において走査型
電子顕微鏡は、電子ビーム22を発生するための電子銃
21と、電子ビーム22を集束して試料25表面へ照射
するためのコンデンサレンズ23および対物レンズ24
と、集束電子ビーム22を試料表面上で走査させるため
の偏向コイル26と、電子ビーム22の照射により試料
から発生した2次電子27を検出するための検出器28
とから構成される。次にこの電子顕微鏡の動作について
説明する。電子銃21より発生した電子ビーム22は、
コンデンサレンズ23および対物レンズ24により試料
25の表面に集束され、偏向コイル26によりその進行
方向が制御されて試料25上を走査する。このとき、集
束電子ビーム22が照射された試料25の表面からは2
次電子27が発生し、この2次電子27を検出器28を
用いて検出することにより、試料25の表面の拡大像を
得ることができる。
FIG. 2 is a diagram showing the principle of a scanning electron microscope used for the above-mentioned purpose. In FIG. 2, the scanning electron microscope includes an electron gun 21 for generating an electron beam 22, a condenser lens 23 and an objective lens 24 for focusing the electron beam 22 and irradiating it onto the surface of a sample 25.
, a deflection coil 26 for scanning the focused electron beam 22 over the sample surface, and a detector 28 for detecting secondary electrons 27 generated from the sample by irradiation with the electron beam 22.
It consists of Next, the operation of this electron microscope will be explained. The electron beam 22 generated from the electron gun 21 is
The light is focused onto the surface of the sample 25 by the condenser lens 23 and the objective lens 24, and its traveling direction is controlled by the deflection coil 26 to scan the sample 25. At this time, from the surface of the sample 25 irradiated with the focused electron beam 22, 2
Secondary electrons 27 are generated, and by detecting these secondary electrons 27 using a detector 28, an enlarged image of the surface of the sample 25 can be obtained.

電子ビーム22は光学系(コンデンサレンズ23および
対物レンズ24)により直径10n11またはそれ以下
にまで集束することができるため、非常に高解像な試料
観察を行なうことができる。
Since the electron beam 22 can be focused to a diameter of 10n11 or less by the optical system (condenser lens 23 and objective lens 24), extremely high-resolution sample observation can be performed.

[発明が解決しようとする問題点] ところで、最近の半導体素子の回路寸法は非常に微細化
されるとともに、3次元方向に回路素子が形成されるよ
うになっために、従来の走査型電子顕微鏡では観察に支
障をきたす場合が生じてきている。
[Problems to be Solved by the Invention] Incidentally, the circuit dimensions of recent semiconductor devices have become extremely fine, and circuit elements are now formed in three dimensions, making it difficult for conventional scanning electron microscopes to However, there are cases where observation becomes difficult.

第3図は上述の従来の走査型電子顕微鏡観察の問題点を
説明するための図であり、第2図と対応する部分には同
一の参照番号が付されている。ここで被観察試料33に
は深い溝36が形成されている。このような深い溝36
は、たとえば半導体装置においては、いわゆる°゛溝掘
キャパシタ”を有するダイナラミックRAM(ランダム
アクセスメモリ)のキャパシタや、素子間分離のために
形成される幅0.5〜1μ髄、深さ2〜5μ11!!i
!度の深くて深い溝に対応する。このような深い溝36
の底部34を観察する場合、入射した電子ビーム22に
より発生した2次電子35は、試料33の表面に到達す
るまでに溝36の側壁に捕捉されてしまい検出器28に
より2次電子35を検出することができず、深い溝36
の底部34を観察することができないという問題点があ
った。
FIG. 3 is a diagram for explaining the above-mentioned problems of conventional scanning electron microscopy, and parts corresponding to those in FIG. 2 are given the same reference numerals. Here, a deep groove 36 is formed in the sample 33 to be observed. Such a deep groove 36
For example, in a semiconductor device, a dynamic RAM (random access memory) capacitor having a so-called "grooved capacitor" or a capacitor with a width of 0.5 to 1 μm and a depth of 2 to 1 μm formed for isolation between elements is used. 5μ11!!i
! Corresponds to deep and deep grooves. Such a deep groove 36
When observing the bottom 34 of the sample 33, the secondary electrons 35 generated by the incident electron beam 22 are captured by the side walls of the groove 36 before reaching the surface of the sample 33, and the secondary electrons 35 are detected by the detector 28. deep groove 36
There was a problem in that it was not possible to observe the bottom part 34 of.

それゆえ、この発明の目的は、上述のような問題点を除
去し、狭くて深い溝の底部の観察も可能な走査型電子顕
微鏡を提供することである。
Therefore, an object of the present invention is to provide a scanning electron microscope that eliminates the above-mentioned problems and allows observation of the bottom of a narrow and deep groove.

[問題点を解決するための手段] この発明にかかる走査型電子顕微鏡は、対物レンズと試
料表面との間に2次電子を引出すための第1電極を設け
るとともに、この第1電極と試料表面へ照射される電子
ビームの進路との間を第2のTs 4Mを用いてシール
ドするようにしたものである。
[Means for Solving the Problems] The scanning electron microscope according to the present invention includes a first electrode for extracting secondary electrons between the objective lens and the sample surface, and a contact between the first electrode and the sample surface. A second Ts 4M is used to shield the path between the electron beam and the path of the electron beam irradiated to the target.

また、第1の電極は試料に対し正の電位に保たれるとと
もに、第2の電極は接地電位に保たれる。
Further, the first electrode is kept at a positive potential with respect to the sample, and the second electrode is kept at a ground potential.

[作用] 試料に対し正電位にされた第1電極の電界により深い溝
の底部で発生した2次電子は溝から引出され、検出器に
よる2次電子の検出が可能となるとともに、第2N極に
より、第1電極の電界が入射電子ビームに与える影響を
無視し1qるものとすることができる。
[Function] Secondary electrons generated at the bottom of the deep groove are drawn out from the groove by the electric field of the first electrode set to a positive potential with respect to the sample, making it possible for the detector to detect the secondary electrons, and Therefore, the influence of the electric field of the first electrode on the incident electron beam can be ignored and assumed to be 1q.

[発明の実施例コ 第1図はこの発明の一実施例である走査型電子顕微鏡の
概略構成を示す部分拡大図である。第1図において、第
2図および第3図に示される従来の走査型電子顕微鏡と
対応する部分には同一の参照番号が付されている。この
発明の特徴として、対物レンズ24と試料33表面との
間に、2次電子15を引出すための予備電極16と、予
備電極16が電子ビーム22へ及ぼす影響を除去するた
めのシールド17とが設けられる。予備?!ff116
は試料33に対し正電位に保たれるとともに、シールド
17は接地電位に設定される。シールド17は、予備電
極16の電界が電子ビーム22に及ばず悪影響を効果的
に排除するように、その形状および配置位置が最適化さ
れる。次に動作について説明する。
Embodiment of the Invention FIG. 1 is a partially enlarged view showing the schematic structure of a scanning electron microscope which is an embodiment of the invention. In FIG. 1, parts corresponding to those of the conventional scanning electron microscope shown in FIGS. 2 and 3 are given the same reference numerals. The present invention is characterized in that a preliminary electrode 16 for extracting secondary electrons 15 and a shield 17 for removing the influence of the preliminary electrode 16 on the electron beam 22 are provided between the objective lens 24 and the surface of the sample 33. provided. spare? ! ff116
is maintained at a positive potential with respect to the sample 33, and the shield 17 is set at a ground potential. The shape and position of the shield 17 are optimized so that the electric field of the preliminary electrode 16 does not reach the electron beam 22 and effectively eliminates any adverse effects. Next, the operation will be explained.

電子ビーム22が、対物レンズ24を介して試料33表
面に形成された狭くて深い満36の底部34へ照射され
ると、溝36の底部34の電子ビーム22が照射された
領域からは2次電子15が発生する。ここまでの動作は
従来の走査型電子顕微鏡と同一である。次に、溝36の
底部34で発生した2次電子15は、試料33に対し正
電位に保たれた予備電極16による電界によって満36
から引出され、検出器28に到達する。これにより従来
不可能であった深くて狭い満36の底部34を観察する
ことが可能となる。
When the electron beam 22 is irradiated through the objective lens 24 to the narrow and deep bottom 34 formed on the surface of the sample 33, a secondary beam irradiates from the area of the bottom 34 of the groove 36 irradiated with the electron beam 22. Electrons 15 are generated. The operation up to this point is the same as that of a conventional scanning electron microscope. Next, the secondary electrons 15 generated at the bottom 34 of the groove 36 are filled with 36
and reaches the detector 28. This makes it possible to observe the deep and narrow bottom 34, which was previously impossible.

ここで、予備電極16による電界が電子ビーム22の進
行に悪影響と及ぼすことが懸念される。
Here, there is a concern that the electric field generated by the preliminary electrode 16 may adversely affect the progress of the electron beam 22.

この悪影響は、試料への電子ビーム照射による試料の損
傷を防止するために電子ビーム22のエネルギをIKe
Vあるいはそれ以下までに下げたときに特に顕著となる
。この悪影響は、電子ビーム220入射進路と予備電極
16との間に設けられた接地電位のシールド17による
遮蔽効果により除去することができる。これにより電子
ビーム22の進行方向に何ら影響を及ぼすことなく確実
に2次電子15を引出し、試料33の満36の底部34
の拡大像を得ることができる。
This adverse effect is due to the fact that the energy of the electron beam 22 is reduced to IKe in order to prevent damage to the sample due to electron beam irradiation.
This becomes especially noticeable when the voltage is lowered to V or lower. This adverse effect can be eliminated by the shielding effect of the ground potential shield 17 provided between the incident path of the electron beam 220 and the preliminary electrode 16. As a result, the secondary electrons 15 are reliably extracted without any influence on the traveling direction of the electron beam 22, and the bottom 36 of the sample 33 is
An enlarged image of the image can be obtained.

[発明の効果] 以上のように、この発明によれば、試料に対し正電位を
有する予備電極を2次電子引出用として設けるとともに
、予備電極と入射電子ビームの進路との間に接地電位の
シールドを設吠るように構成したので、予備電極の悪影
響を及ぼすことなく、従来の走査型電子顕微鏡では不可
能であった狭くて深い溝の底部の観察が可能となる。
[Effects of the Invention] As described above, according to the present invention, a preliminary electrode having a positive potential with respect to the sample is provided for extracting secondary electrons, and a ground potential is provided between the preliminary electrode and the path of the incident electron beam. Since the shield is constructed in such a way that the shield is installed, it is possible to observe the bottom of a narrow and deep groove, which is impossible with a conventional scanning electron microscope, without the adverse effects of the preliminary electrode.

【図面の簡単な説明】[Brief explanation of drawings]

第1図はこの発明の一実施例である走査型電子顕微鏡の
概念的構成を示すための概略部分拡大図である。第2図
は従来の走査型電子顕微鏡の動作原理を示すための概略
構成図である。第3図は従来の走査型電子im鏡の問題
点を示すための図であり、走査型電子類1iiIl鏡の
概略部分拡大図である。 図において、15は2次電子、16は補助電極(第1電
極)、17はシールド(第2電極)、22は電子ビーム
、24は対物レンズ、28は検出器、33は試料、34
は満の底部、36は試料33に設けられた狭くて深い溝
である。 なお、図中、同一符号は同一または相当部分を示す。 代理人   大  岩  増  8 第1図 15:  二大電″+       22:  ・電子
ビ°−416−補助・ミオ暑           2
4:   #’わヮ、ツエ、。 17: シー”F’           33:  
を岐イ咋28;  検出2傾            
34:  !鼻り&帥36:# 第2図 21:電子銃     25:  往半斗22: 電子
ビー4     26; イ都句コイ1し23; コン
↑゛′ンすし)ス”     27:  二次′電子2
4:  り↑鞠しレス+l      2s :  倹
巴器〜晃3図 22・電子!ニー4   35:  二S六電テ24−
7丁・1勿し)ス゛        28:  序尖゛
 呂2ζ、33:試打     36:  =t 34:構り底押 手続補正書(自発) か
FIG. 1 is a schematic partially enlarged view showing the conceptual configuration of a scanning electron microscope which is an embodiment of the present invention. FIG. 2 is a schematic configuration diagram showing the operating principle of a conventional scanning electron microscope. FIG. 3 is a diagram for illustrating the problems of the conventional scanning type electronic IM mirror, and is a schematic partial enlarged view of the scanning type electronic IM mirror. In the figure, 15 is a secondary electron, 16 is an auxiliary electrode (first electrode), 17 is a shield (second electrode), 22 is an electron beam, 24 is an objective lens, 28 is a detector, 33 is a sample, 34
36 is a narrow and deep groove provided in the sample 33. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. Agent Masu Oiwa 8 Fig. 1 15: Two major electric power stations + 22: ・Electronic TV-416-Auxiliary・Miohatsu 2
4: #'Wow, Tsue. 17: C”F’ 33:
Detection 2 tilt
34: ! 36: #2 Figure 21: Electron gun 25: Ouhanto 22: Electronic bee 4 26;
4: ri↑marish reply + l 2s: Thrifty machine ~ Akira 3 Figure 22 - Electronics! Knee 4 35: 2S Rokuden Te 24-
7 guns / 1) Su゛ 28: First point゛ ro 2ζ, 33: Test shot 36: =t 34: Draft amendment for bottom push procedure (voluntary)?

Claims (1)

【特許請求の範囲】 少なくとも対物レンズを介して集束電子ビームを試料表
面へ照射し、前記照射された試料表面からの2次電子を
検出することにより前記照射された試料表面の拡大像を
得る走査型電子顕微鏡であって、 前記対物レンズと前記試料表面との間に前記集束電子ビ
ームの進路を遮らないように設けられ、少なくとも測定
時には前記試料に対し正の電位を有する第1の電極と、 前記集束電子ビームの進路と前記第1の電極との間に設
けられ、少なくとも測定時には接地電位にされる第2の
電極とを備える、走査型電子顕微鏡。
[Scope of Claims] Scanning for obtaining an enlarged image of the irradiated sample surface by irradiating the sample surface with a focused electron beam through at least an objective lens and detecting secondary electrons from the irradiated sample surface. a first electrode that is provided between the objective lens and the sample surface so as not to obstruct the path of the focused electron beam, and that has a positive potential with respect to the sample at least during measurement; A scanning electron microscope, comprising: a second electrode that is provided between the path of the focused electron beam and the first electrode, and is brought to a ground potential at least during measurement.
JP60238833A 1985-10-23 1985-10-23 Scanning type electron microscope Pending JPS6297246A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP60238833A JPS6297246A (en) 1985-10-23 1985-10-23 Scanning type electron microscope

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP60238833A JPS6297246A (en) 1985-10-23 1985-10-23 Scanning type electron microscope

Publications (1)

Publication Number Publication Date
JPS6297246A true JPS6297246A (en) 1987-05-06

Family

ID=17035949

Family Applications (1)

Application Number Title Priority Date Filing Date
JP60238833A Pending JPS6297246A (en) 1985-10-23 1985-10-23 Scanning type electron microscope

Country Status (1)

Country Link
JP (1) JPS6297246A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4928010A (en) * 1986-11-28 1990-05-22 Nippon Telegraph And Telephone Corp. Observing a surface using a charged particle beam
US5412210A (en) * 1990-10-12 1995-05-02 Hitachi, Ltd. Scanning electron microscope and method for production of semiconductor device by using the same
US5594245A (en) * 1990-10-12 1997-01-14 Hitachi, Ltd. Scanning electron microscope and method for dimension measuring by using the same
US5866904A (en) * 1990-10-12 1999-02-02 Hitachi, Ltd. Scanning electron microscope and method for dimension measuring by using the same
EP0930638A1 (en) * 1990-10-12 1999-07-21 Hitachi, Ltd. Scanning electron microscope, production method for semiconductor device by using the same, image forming method

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4928010A (en) * 1986-11-28 1990-05-22 Nippon Telegraph And Telephone Corp. Observing a surface using a charged particle beam
US5412210A (en) * 1990-10-12 1995-05-02 Hitachi, Ltd. Scanning electron microscope and method for production of semiconductor device by using the same
US5594245A (en) * 1990-10-12 1997-01-14 Hitachi, Ltd. Scanning electron microscope and method for dimension measuring by using the same
US5866904A (en) * 1990-10-12 1999-02-02 Hitachi, Ltd. Scanning electron microscope and method for dimension measuring by using the same
EP0930638A1 (en) * 1990-10-12 1999-07-21 Hitachi, Ltd. Scanning electron microscope, production method for semiconductor device by using the same, image forming method
US5969357A (en) * 1990-10-12 1999-10-19 Hitachi, Ltd. Scanning electron microscope and method for dimension measuring by using the same
US6114695A (en) * 1990-10-12 2000-09-05 Hitachi, Ltd. Scanning electron microscope and method for dimension measuring by using the same

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