JPS63231842A - Electric field ionization type ion source - Google Patents
Electric field ionization type ion sourceInfo
- Publication number
- JPS63231842A JPS63231842A JP6468787A JP6468787A JPS63231842A JP S63231842 A JPS63231842 A JP S63231842A JP 6468787 A JP6468787 A JP 6468787A JP 6468787 A JP6468787 A JP 6468787A JP S63231842 A JPS63231842 A JP S63231842A
- Authority
- JP
- Japan
- Prior art keywords
- ion source
- vacuum
- refrigerator
- ion
- degree
- 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
- 230000005684 electric field Effects 0.000 title description 2
- 238000001816 cooling Methods 0.000 claims abstract description 19
- 238000010884 ion-beam technique Methods 0.000 abstract description 20
- 238000010438 heat treatment Methods 0.000 abstract description 2
- 238000007599 discharging Methods 0.000 abstract 1
- 238000012544 monitoring process Methods 0.000 abstract 1
- 238000001179 sorption measurement Methods 0.000 abstract 1
- 150000002500 ions Chemical class 0.000 description 46
- 238000010586 diagram Methods 0.000 description 5
- 239000007789 gas Substances 0.000 description 5
- 239000001307 helium Substances 0.000 description 4
- 229910052734 helium Inorganic materials 0.000 description 4
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 4
- 238000010894 electron beam technology Methods 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 238000005468 ion implantation Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 108010083687 Ion Pumps Proteins 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 150000002466 imines Chemical class 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 229910001338 liquidmetal Inorganic materials 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J2237/00—Discharge tubes exposing object to beam, e.g. for analysis treatment, etching, imaging
- H01J2237/06—Sources
- H01J2237/08—Ion sources
- H01J2237/0802—Field ionization sources
- H01J2237/0807—Gas field ion sources [GFIS]
Landscapes
- Electron Sources, Ion Sources (AREA)
Abstract
Description
【発明の詳細な説明】
［概要］
電界電離型イオン源において、イオン源に接続した冷凍
機に冷却温度を制御できる機能を附加し、動作停止後、
冷却温度を徐々に上昇させて冷却面からガス放出の速度
を小さくし、イオン源の圧力が上昇しないようする。そ
うすれば、放電が発生せずに、エミッタ先端の形状が安
定に保持される。[Detailed Description of the Invention] [Summary] In a field ionization type ion source, a function that can control the cooling temperature is added to the refrigerator connected to the ion source, and after the operation stops,
The cooling temperature is gradually increased to reduce the rate of gas release from the cooling surface and to prevent the pressure of the ion source from increasing. In this way, no discharge occurs and the shape of the emitter tip is stably maintained.
［産業上の利用分野］
本発明は集束イオンビーム装置などに用いられる電界電
離型イオン源に関する。[Industrial Application Field] The present invention relates to a field ionization type ion source used in a focused ion beam device or the like.
ＩＣなど半導体装置の製造プロセスにおいては、デバイ
スの微細化、高密度化に伴ってイオンビーム技術が注目
されており、その開発研究が鋭意進行中である。このよ
うな集束イオンビーム装置において、イオン源は装置の
性能を左右する重要な部材で、その安定化が望まれてい
る。BACKGROUND ART In the manufacturing process of semiconductor devices such as ICs, ion beam technology is attracting attention as devices become smaller and more dense, and research and development thereof is actively underway. In such a focused ion beam device, the ion source is an important component that affects the performance of the device, and its stability is desired.
［従来の技術］
さて、従来のイオン注入装置は全面にイオンを照射する
方式であったが、集束イオンビーム装置は細い集束ビー
ムによって、例えば、電子ビーム露光の様にマスクレス
露光が可能になるもので、且つ、イオンビームは電子ビ
ームに比べて物体（例えば、レジスト）中での散乱が小
さい等の利点がある。そのため、次代のサブミクロン以
下の微線構造デバイス製作用として多くのプロセス技術
者が期待しており、また、露光技術のみならず、デポジ
ションやエツチングにも利用できるものである。[Conventional technology] Conventional ion implantation equipment irradiates the entire surface with ions, but focused ion beam equipment uses a narrow focused beam to enable maskless exposure similar to electron beam exposure, for example. In addition, ion beams have advantages over electron beams, such as less scattering in objects (for example, resist). Therefore, many process engineers are looking forward to using it for the production of next-generation submicron or fine line structure devices, and it can also be used not only for exposure technology but also for deposition and etching.
このような集束イオンビーム装置の概要図を第２図に示
しており、本例はマスクレスイオン注入用のもので、本
装置はイオン源（イオン銃）１゜コンデンサレンズ２，
４．質量分析器３．ビーム走査系５．試料６から構成さ
れ、且つ、図示していないが、イオン源にイオンポンプ
、試料側にターボポンプなどの排気系を備えている。図
示のように、その構造は公知の電子ビーム装置とほぼ類
似しているが、大きな相異点は質量分析器３を具備して
いることで、これは複数種のイオンをイオン源から放射
した場合、それを分離して１種類のイオンのみ照射させ
るために配置されているものである。A schematic diagram of such a focused ion beam device is shown in FIG. 2. This example is for maskless ion implantation, and this device consists of an ion source (ion gun), 1° condenser lens, 2
4. Mass spectrometer 3. Beam scanning system 5. Although not shown, the ion source is equipped with an ion pump and the sample side is equipped with an exhaust system such as a turbo pump. As shown in the figure, its structure is almost similar to a known electron beam device, but the major difference is that it is equipped with a mass analyzer 3, which emitted multiple types of ions from an ion source. In this case, it is arranged to separate the ions and irradiate only one type of ion.
この集束イオンビーム装置において最も重要なものは、
高輝度集束イオンビームを得るためのイオン源である。The most important things in this focused ion beam device are:
This is an ion source for obtaining a high-intensity focused ion beam.
このイオン源は集束イオンビーム装置の用途を拡げるた
めに、種々のイオン種の生成が必要になるが、初期に液
体金属イオン源を用いたＧａ集集束オンビーム装置が発
表されて以来、液体金属を用いたＥＨＤ形イオン源が著
名となっている。しかし、気体を用いた電界電離型イオ
ン源の開発も進められている。This ion source requires the generation of various ion species in order to expand the applications of focused ion beam devices, but since the early announcement of a Ga focused on-beam device using a liquid metal ion source, there has been a The EHD type ion source used has become famous. However, field ionization type ion sources using gas are also being developed.
第３図はそのような電界電離型イオン源の要部を図示し
ており、図中の１１はイオン放出用のエミッタ（タング
ステン針）、１２は対向電極で、イオン源全体の雰囲気
はＩＱ Ｔｏｒｒ程度の高真空にし、イオン放出用の
エミッタを２０にあるいはそれ以下の極低温に冷却し、
エミッタ先端に高電圧を印加して、例えば、ヘリウム（
■ｅ）イオンビームを放出させる。Figure 3 shows the main parts of such a field ion source. In the figure, 11 is an emitter (tungsten needle) for emitting ions, 12 is a counter electrode, and the atmosphere of the entire ion source is IQ Torr. The emitter for ion emission is cooled to a cryogenic temperature of 20℃ or lower.
By applying a high voltage to the emitter tip, e.g. helium (
■e) Emit an ion beam.
このように、絶対零度近くまでエミッタを冷却させるた
めに、イオン源全体は冷凍機に密着させて冷凍しており
、第４図はその構成概要を示している。２０はイオン源
、２１は冷凍機で、冷却方法は液体ヘリウムをイオン源
に供給する方式のものである。In this way, in order to cool the emitter to near absolute zero, the entire ion source is frozen in close contact with a refrigerator, and FIG. 4 shows an outline of its configuration. 20 is an ion source, 21 is a refrigerator, and the cooling method is a type in which liquid helium is supplied to the ion source.
［発明が解決しようとする問題点］
ところで、従来、上記のようにしてイオン源を動作させ
た後、動作の停止ためには高電圧印加を停止していたが
、そうすれば、エミッタ表面に不純物が吸着して、次に
再動作させるためにはエミッタ表面を電界蒸発によって
清浄化する必要があった。しかし、電界蒸発する毎にエ
ミッタ先端の曲率半径が大きくなる等、エミッタ先端の
形状が ゛変化して、高輝度イオンビームが安定して得
られないと云う問題があった。[Problems to be Solved by the Invention] Conventionally, after operating the ion source as described above, the application of high voltage was stopped in order to stop the operation. After impurities were adsorbed, the emitter surface had to be cleaned by field evaporation in order to operate again. However, each time the electric field evaporates, the radius of curvature of the emitter tip increases, and the shape of the emitter tip changes, making it difficult to stably obtain a high-intensity ion beam.
そこで、現在、エミッタ先端に高電圧を印加したまま動
作を停止する方法を採っている。ところが、そうすると
、冷凍機の動作を停止させた時、イオン源や冷凍機の冷
却面に吸着されている吸着ガスが温度上昇によって一度
に大量放出され、真空度が一時的に１０’Ｔｏｒｒ程度
にまで低下する。そうすれば、その圧力上昇に伴ってエ
ミッタ先端で放電が起こり、先端形状が変化して破壊さ
れる。Therefore, the current method is to stop the operation while applying a high voltage to the tip of the emitter. However, when the refrigerator operation is stopped, a large amount of the adsorbed gas adsorbed on the ion source and the cooling surface of the refrigerator is released at once due to the temperature rise, and the degree of vacuum temporarily drops to about 10'Torr. decreases to Then, as the pressure increases, a discharge occurs at the tip of the emitter, changing the shape of the tip and destroying it.
従って、同じく高輝度イオンビームが安定して得られな
い問題がある。Therefore, there is also the problem that a high-intensity ion beam cannot be stably obtained.
本発明は、このような問題点を解消させて、エミッタ先
端の形状を一定に保持して、高輝度イミンビームが安定
して得られる電界電離型イオン源を提案するものである
。The present invention solves these problems and proposes a field ion source that can stably obtain a high-intensity imine beam by keeping the shape of the emitter tip constant.
Ｅ問題点を解決するための手段］
その目的は、冷凍機に冷却温度を制御できる機能を附加
し、イオン源の動作を停止させた後、冷却温度を徐々に
上昇させ、冷却面から吸着ガスを徐々に放出して、イオ
ン源の圧力を上昇しないようにした電界電離型イオン源
によって達成される。Measures to Solve Problem E] The purpose is to add a function that can control the cooling temperature to the refrigerator, and after stopping the operation of the ion source, gradually increase the cooling temperature, and remove the adsorbed gas from the cooling surface. This is achieved using a field ion source that gradually releases the ions without increasing the pressure of the ion source.
［作用］
即ち、本発明は、冷凍機に冷却温度を制御できる機能を
附加し、動作停止後、冷却温度を徐々に上昇させて冷却
面から吸着ガスを徐々に放出させ、イオン源の真空度（
圧力）が悪くならないようする。そうすれば、放電が発
生せず、エミッタ先端が傷まない。従って、再現性の良
い安定した高輝度イオンビームが得られる。[Function] That is, the present invention adds a function that can control the cooling temperature to the refrigerator, and after the operation is stopped, the cooling temperature is gradually increased to gradually release the adsorbed gas from the cooling surface, and the vacuum degree of the ion source is adjusted. (
Make sure that the pressure does not worsen. This way, no discharge will occur and the emitter tip will not be damaged. Therefore, a stable high-intensity ion beam with good reproducibility can be obtained.
［実施例］ 以下、実施例によって詳細に説明する。[Example] Hereinafter, it will be explained in detail using examples.
第１図は本発明にかかるイオン源冷却の構成概要図を示
しており、２０ばイオン源、２１は冷凍機。FIG. 1 shows a schematic diagram of the configuration of ion source cooling according to the present invention, where 20 is an ion source and 21 is a refrigerator.
２２は抵抗加熱ヒータである。且つ、加熱ヒータ２２は
電源２３の電圧を加減して加熱電流が制御され、その電
源２３は真空計２４の真空度を監視している制御系２５
に接続している。22 is a resistance heater. In addition, the heating current of the heater 22 is controlled by adjusting the voltage of a power source 23, and the power source 23 is connected to a control system 25 that monitors the degree of vacuum of a vacuum gauge 24.
is connected to.
このように構成して、動作停止後、冷凍機はそのまま引
続き動作させ、また、真空排気も続行させておく。なお
、真空排気と高電圧印加は従来より動作停止後も常に動
作させているものである。With this configuration, after the operation is stopped, the refrigerator continues to operate, and evacuation continues. Incidentally, vacuum evacuation and high voltage application are conventionally always operated even after the operation is stopped.
そうして、イオン源の真空度を計測し、その圧力（真空
度）が設定値を越えないように制御するものである。The degree of vacuum of the ion source is then measured and controlled so that the pressure (degree of vacuum) does not exceed a set value.
具体的な実施例を説明すると、イオン源だけの圧力を直
接測定できないので、集束イオンビーム装置の集束コラ
ムの圧力を検出し、その圧力の上限値を１０−’パスカ
ル（１０−６Ｔｏｒｒ程度）に設定する。To explain a specific example, since the pressure of only the ion source cannot be directly measured, the pressure of the focusing column of the focused ion beam device is detected and the upper limit of the pressure is set to 10-' Pascal (about 10-6 Torr). Set.
そして、冷凍機の液体ヘリウムは供給し、冷凍機はその
まま動作させておいて、制御系２５によって０．５に／
秒の温度上昇になるように加熱ヒータ２２の電流を増加
させる。１０−４パスカルの圧力上限値に達すると、加
熱し−タ２２の電流増加を抑制する。Then, liquid helium is supplied to the refrigerator, the refrigerator is left operating, and the control system 25 adjusts the temperature to 0.5/1.
The current of the heater 22 is increased so that the temperature rises in seconds. When the pressure reaches the upper limit of 10-4 Pascals, the increase in current in the heater 22 is suppressed.
かくして、イオン源の温度が常温（２９０Ｋ）に戻った
時点で、冷凍機の液体ヘリウム供給を停止し、高電圧印
加状態のまま、また、真空排気のまま停止しておく。Thus, when the temperature of the ion source returns to room temperature (290 K), the supply of liquid helium to the refrigerator is stopped, and the refrigerator is stopped with high voltage applied and vacuum evacuation.
このようにすれば、エミッタ先端から放電を発生させる
ことなく、イオン源を常温に戻し、エミッタに高電圧を
印加したまま停止させることができる。従って、エミッ
タ先端は清浄に保たれ、且つ、傷つけられることもない
から、このようなイオン源から再現性の良い安定した高
輝度イオンビームが得られる。In this way, the ion source can be returned to room temperature and stopped while a high voltage is applied to the emitter without generating discharge from the emitter tip. Therefore, since the emitter tip is kept clean and undamaged, a stable, high-intensity ion beam with good reproducibility can be obtained from such an ion source.
［発明の効果］
以上の説明から明らかなように、本発明によれば安定し
た高輝度イオンビームが得られ、電界電離型イオン源を
有する集束イオンビーム装置の性能向上に大きく寄与す
るものである。[Effects of the Invention] As is clear from the above description, according to the present invention, a stable high-intensity ion beam can be obtained, and it greatly contributes to improving the performance of a focused ion beam device having a field ionization type ion source. .
第１図は本発明にかかるイオン源冷却の構成概要図、
第２図は集束イオンビーム装置の概要図、第３図は電界
電離型イオン源の概要図、第４図は従来のイオン源冷却
の構成概要図である。
図において、
１．２０はイオン源、 ２１は冷凍機、２２は加熱ヒ
ータ、 ２３は加熱ヒータの電源、２４は真空計、
２５は制御系＋ｉに臼ル；疫・方・３ノフ１
へ゛オｉｌｌンゴ第１図
渾藝君イオ〉と・・−４１虹！
第２図Fig. 1 is a schematic diagram of the configuration of the ion source cooling according to the present invention, Fig. 2 is a schematic diagram of the focused ion beam device, Fig. 3 is a schematic diagram of the field ion source, and Fig. 4 is the conventional ion source cooling. FIG. In the figure, 1.20 is an ion source, 21 is a refrigerator, 22 is a heater, 23 is a power source for the heater, 24 is a vacuum gauge,
25 is for control system + i; epidemic, direction, 3 nof 1
Hey, I'm in love with you! -41 Rainbow! Figure 2
Claims (1)
オン源において、前記冷凍機に冷却温度を制御できる機
能を附加し、前記イオン源の動作を停止させた後、冷却
温度を徐々に上昇させることにより、冷却面から吸着ガ
スを徐々に放出させ、イオン源の圧力が上昇しないよう
にしたことを特徴とする電界電離型イオン源。In a field ionization type ion source that operates while being cooled by a refrigerator, a function that can control the cooling temperature is added to the refrigerator, and after the operation of the ion source is stopped, the cooling temperature is gradually increased. A field ionization type ion source characterized in that the adsorbed gas is gradually released from the cooling surface and the pressure of the ion source does not increase.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6468787A JPS63231842A (en) | 1987-03-18 | 1987-03-18 | Electric field ionization type ion source |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6468787A JPS63231842A (en) | 1987-03-18 | 1987-03-18 | Electric field ionization type ion source |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS63231842A true JPS63231842A (en) | 1988-09-27 |
Family
ID=13265314
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6468787A Pending JPS63231842A (en) | 1987-03-18 | 1987-03-18 | Electric field ionization type ion source |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63231842A (en) |
-
1987
- 1987-03-18 JP JP6468787A patent/JPS63231842A/en active Pending
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