JPH07135144A - Charged particle beam aligner - Google Patents
Charged particle beam alignerInfo
- Publication number
- JPH07135144A JPH07135144A JP5157488A JP15748893A JPH07135144A JP H07135144 A JPH07135144 A JP H07135144A JP 5157488 A JP5157488 A JP 5157488A JP 15748893 A JP15748893 A JP 15748893A JP H07135144 A JPH07135144 A JP H07135144A
- Authority
- JP
- Japan
- Prior art keywords
- charged particle
- particle beam
- mask
- sub
- field
- 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
Landscapes
- Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)
- Electron Beam Exposure (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は、荷電粒子線によりマス
ク上に形成したパターンを半導体用のウエハ等の感光基
板に転写する露光装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus for transferring a pattern formed on a mask by a charged particle beam onto a photosensitive substrate such as a semiconductor wafer.
【0002】[0002]
【従来の技術】従来、この種の装置では、マスクへ照射
する荷電粒子線のビーム電流が大きいと空間電荷効果で
ビームにボケが生じ、マスクのパターンを感光基板へ正
しく転写することが困難となる。このため、ビーム電流
を空間電荷効果の影響が無視できる程度まで小さくして
露光を行なっている。2. Description of the Related Art Conventionally, in this type of apparatus, when the beam current of a charged particle beam with which a mask is irradiated is large, the beam is blurred due to the space charge effect, and it is difficult to correctly transfer the mask pattern onto the photosensitive substrate. Become. For this reason, the exposure is performed with the beam current reduced to such an extent that the effect of the space charge effect can be ignored.
【0003】[0003]
【発明が解決しようとする課題】しかし、ビーム電流が
小さいと露光に長時間を要し、スループットが低下す
る。また、同一の領域を長時間かけて露光するので感光
基板上のレジストが加熱して熱膨張が発生し、露光精度
が低下する。However, if the beam current is small, it takes a long time for exposure and the throughput is lowered. In addition, since the same region is exposed for a long time, the resist on the photosensitive substrate is heated to cause thermal expansion, which lowers the exposure accuracy.
【0004】ところで、荷電粒子線の空間電荷効果とし
て一般に認識されているものは以下の3種類に分類され
る。 荷電粒子線同士が衝突して互いのエネルギーを交換
する結果、荷電粒子線のエネルギー幅が広がる効果。 荷電粒子線同士が衝突することにより互いの軌道が
曲げられる効果。 荷電粒子線が持つ空間電荷のため荷電粒子線のビー
ムが全体的に広がり、結果的に荷電粒子線の集束位置が
遠くへ移動する効果。By the way, the generally recognized space charge effects of charged particle beams are classified into the following three types. As a result of the charged particle beams colliding with each other and exchanging their energies, the energy width of the charged particle beams widens. The effect that the orbits of the charged particle beams are bent when they collide with each other. Due to the space charge of the charged particle beam, the beam of the charged particle beam spreads as a whole, resulting in the focal position of the charged particle beam moving far.
【0005】荷電粒子線を集束させる投影レンズにtran
sverse色収差(視野色収差)が十分に補正されたものを
用いる限り、の効果によるビームのボケは小さく、通
常は無視できる。また、荷電粒子線が集中するクロスオ
ーバー近傍では、上述したの空間電荷効果が比較的大
きくなる。しかし、このような領域は荷電粒子線の全光
路長の1/100〜1/10程度に過ぎず、したがって
の効果による空間電荷効果も問題にはならない。の
空間電荷効果に関しては、マスクに形成されたパターン
(ビーム透過部分に相当する。)を通過して感光基板へ
向う荷電粒子線同士がいかに離れていても、マスクのパ
ターンを通過する全ビーム電流に比例したボケが生じ
る。特にマスク上の比較的大きな領域を一度に照射して
その範囲内のパターンを一括して感光基板へ転写する露
光装置では、照射範囲全体でみたときのビーム電流が、
パターンを一々描画する描画式の露光装置等と比較して
相当大きいため、感光基板上で大きなボケが生じる。こ
のボケを避けるため、従来の装置ではマスクへ照射する
ビーム電流そのものをごく小さく設定せざるを得なかっ
た。Tran for a projection lens that focuses a charged particle beam
As long as the sverse chromatic aberration (visual field chromatic aberration) is sufficiently corrected, the beam blur due to the effect of is small and can usually be ignored. Further, in the vicinity of the crossover where the charged particle beams are concentrated, the above-mentioned space charge effect becomes relatively large. However, such a region is only about 1/100 to 1/10 of the total optical path length of the charged particle beam, and the space charge effect due to this effect does not pose a problem. Regarding the space charge effect of, the total beam current passing through the pattern of the mask, no matter how far apart the charged particle beams are, which are passing through the pattern (corresponding to the beam transmitting portion) formed in the mask and toward the photosensitive substrate. Blurring occurs in proportion to. In particular, in an exposure apparatus that irradiates a relatively large area on the mask at one time and transfers the patterns within that area to the photosensitive substrate at once, the beam current when viewed over the entire irradiation area is
Since it is considerably larger than a drawing type exposure apparatus that draws patterns one by one, a large blur occurs on the photosensitive substrate. In order to avoid this blur, in the conventional apparatus, the beam current itself for irradiating the mask had to be set to a very small value.
【0006】本発明の目的は、空間電荷効果による荷電
粒子線のボケを抑制しつつ従来よりも効率よく露光を行
ない得る荷電粒子線露光装置を提供することにある。An object of the present invention is to provide a charged particle beam exposure apparatus capable of performing exposure more efficiently than before while suppressing blurring of the charged particle beam due to the space charge effect.
【0007】[0007]
【課題を解決するための手段】一実施例を示す図1およ
び図2に対応付けて説明すると、本発明は、荷電粒子線
Bによりマスク5の特定範囲SFを同時に照射し、当該
特定範囲SFに形成されたパターン5aを投影レンズ
6,7を介して感光基板Wに転写する荷電粒子線露光装
置に適用される。そして、マスク5上の特定範囲SFに
おけるパターン5aの充填率が大きいほど投影レンズ
6,7の焦点距離が短くなるように当該投影レンズ6,
7を制御する焦点制御手段10,62,72を備えるこ
とにより上述した目的を達成する。ここでパターン5a
の充填率とは、マスク5の特定範囲SF内に形成された
パターン5aの面積を当該特定範囲SFの面積で除した
値をいう。請求項2の装置では、焦点制御手段が、投影
レンズ6,7に挿入された金属製の円筒62,72への
印加電圧を調節して投影レンズ6,7の焦点距離を変化
させる。1 and 2, which show an embodiment, the present invention is directed to irradiating a specific area SF of a mask 5 with a charged particle beam B at the same time to obtain the specific area SF. It is applied to a charged particle beam exposure apparatus that transfers the pattern 5a formed on the photosensitive substrate W via the projection lenses 6 and 7. Then, the larger the filling rate of the pattern 5a in the specific range SF on the mask 5, the shorter the focal lengths of the projection lenses 6 and 7 are.
The above-mentioned object is achieved by providing the focus control means 10, 62, 72 for controlling the optical axis 7. Pattern 5a here
The filling rate is a value obtained by dividing the area of the pattern 5a formed in the specific range SF of the mask 5 by the area of the specific range SF. In the apparatus of claim 2, the focus control means changes the focal length of the projection lenses 6 and 7 by adjusting the voltage applied to the metal cylinders 62 and 72 inserted in the projection lenses 6 and 7.
【0008】[0008]
【作用】1回の露光によりマスク5上の特定範囲SFに
照射される荷電粒子線Bのビーム電流が当該特定範囲S
Fの面積に拘らず一定とすると、特定範囲SFのパター
ン5aを通過する荷電粒子線Bのビーム電流は当該特定
範囲SFにおけるパターン5aの充填率に応じて変化
し、充填率が大きいほどビーム電流は増加する。このた
め、パターン充填率が大きくなるほどマスク5を透過し
た荷電粒子線Bの上記の空間電荷効果が大きくなり、
その集束位置は遠方へ移動しようとする。ここで、本発
明ではパターン5aの充填率が大きいほど投影レンズ
6,7の焦点距離が短くなるように投影レンズ6,7が
制御されるので、空間電荷効果による焦点の変化と投影
レンズ6,7の焦点距離の変化とが相殺され、感光基板
W上での荷電粒子線Bのボケが抑制される。The beam current of the charged particle beam B with which the specific area SF on the mask 5 is irradiated by one exposure is changed to the specific area S.
If it is constant regardless of the area of F, the beam current of the charged particle beam B passing through the pattern 5a in the specific range SF changes according to the filling rate of the pattern 5a in the specific range SF, and the beam current increases as the filling rate increases. Will increase. Therefore, the greater the pattern filling rate, the greater the space charge effect of the charged particle beam B that has passed through the mask 5,
The focus position is going to move away. Here, in the present invention, since the projection lenses 6 and 7 are controlled so that the larger the filling rate of the pattern 5a is, the shorter the focal lengths of the projection lenses 6 and 7 are. The change in the focal length of No. 7 is offset and the blur of the charged particle beam B on the photosensitive substrate W is suppressed.
【0009】請求項2の装置では、投影レンズ6,7内
に挿入した金属製の円筒62,72への印加電圧を増減
すると、荷電粒子線Bの投影レンズ6,7内の通過速度
が変化して投影レンズ6,7による荷電粒子線Bの屈折
作用が変化する。これにより、投影レンズ6,7の焦点
距離が変化する。In the apparatus of claim 2, when the applied voltage to the metal cylinders 62 and 72 inserted in the projection lenses 6 and 7 is increased or decreased, the passing speed of the charged particle beam B in the projection lenses 6 and 7 changes. Then, the refraction of the charged particle beam B by the projection lenses 6 and 7 changes. As a result, the focal lengths of the projection lenses 6 and 7 change.
【0010】なお、本発明の構成を説明する上記課題を
解決するための手段と作用の項では、本発明を分かり易
くするために実施例の図を用いたが、これにより本発明
が実施例に限定されるものではない。Incidentally, in the section of means and action for solving the above problems for explaining the constitution of the present invention, the drawings of the embodiments are used for the purpose of making the present invention easy to understand. It is not limited to.
【0011】[0011]
【実施例】以下、図1〜図3を参照して本発明の一実施
例を説明する。図1は本実施例の露光装置の概略を示す
もので、1は荷電粒子線の発生源としての電子銃であ
る。この電子銃1から放出された電子ビームBはコンデ
ンサレンズ2で偏向されて偏向器3の中心のクロスオー
バーC1上に結像する。クロスオーバーC1を通過した
電子ビームBは偏向器3により所定の方向へ偏向され、
コンデンサレンズ4で平行ビームに矯正されてマスク5
の特定範囲に到達する。DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows an outline of an exposure apparatus of this embodiment, and 1 is an electron gun as a source of a charged particle beam. The electron beam B emitted from the electron gun 1 is deflected by the condenser lens 2 and forms an image on the crossover C1 at the center of the deflector 3. The electron beam B passing through the crossover C1 is deflected in a predetermined direction by the deflector 3,
Mask 5 after being corrected to a parallel beam by condenser lens 4
Reach a certain range of.
【0012】図2に示すように、マスク5は電子ビーム
を透過させる透過部5a(図中のハッチング領域)が形
成されたものである。マスク5は複数の副視野SFに区
分され、これら副視野SFの一つが図1に示す偏向器3
を通過した電子ビームBで照射される。なお、副視野S
Fの面積や透過部5aの形状は一定でなく、図示の例で
は右側の副視野SFの方が左側の副視野SFより面積が
大きい。また、透過部5aの面積の総和は左側の副視野
SFの方が大きい。As shown in FIG. 2, the mask 5 has a transparent portion 5a (hatched area in the drawing) for transmitting an electron beam. The mask 5 is divided into a plurality of sub-fields of view SF, one of which is the deflector 3 shown in FIG.
The electron beam B that has passed through is irradiated. The sub-field of view S
The area of F and the shape of the transmission part 5a are not constant, and in the illustrated example, the right sub-field SF has a larger area than the left sub-field SF. The total area of the transmissive portion 5a is larger in the left sub-field of view SF.
【0013】図1に示すように、マスク5のいずれか一
つの副視野SFの透過部5aを通過した電子ビームB
は、第1の投影レンズ6で集光されてクロスオーバーC
2に結像する。クロスオーバーC2を通過した電子ビー
ムBは、第2の投影レンズ7により、電子銃1の光軸A
と平行なビームに矯正されてウエハW上の特定位置に到
達する。これによりマスク5の副視野SFに形成された
透過部5aの形状がレンズ6,7の屈折率に応じた倍率
でウエハWのレジスト上に転写される。投影レンズ6,
7は不図示の電源からの供給電流に応じた磁界を発生さ
せるコイル60,70を強磁性体61,71で覆うとと
もに、コイル60,70の内周側に非磁性体、例えば銅
製の円筒62,72を挿入したものである。なお、円筒
62,72は、電子ビームBが通過する不図示の真空容
器内に絶縁状態で支持される。As shown in FIG. 1, the electron beam B which has passed through the transmission part 5a of any one of the sub-fields SF of the mask 5.
Is condensed by the first projection lens 6 and crossed over C
Image to 2. The electron beam B that has passed through the crossover C2 is transmitted by the second projection lens 7 to the optical axis A of the electron gun 1.
The beam is corrected into a beam parallel to and reaches a specific position on the wafer W. As a result, the shape of the transmission part 5a formed in the sub-field of view SF of the mask 5 is transferred onto the resist of the wafer W at a magnification corresponding to the refractive index of the lenses 6 and 7. Projection lens 6,
Reference numeral 7 covers coils 60 and 70 for generating a magnetic field according to a current supplied from a power source (not shown) with ferromagnetic bodies 61 and 71, and a non-magnetic body such as a copper cylinder 62 on the inner peripheral side of the coils 60 and 70. , 72 are inserted. The cylinders 62 and 72 are supported in an insulating state in a vacuum container (not shown) through which the electron beam B passes.
【0014】投影レンズ6,7の円筒62,72には、
CPU10からインターフェース11および電圧増幅器
12を介して正極側の電圧が印加され、この印加電圧に
応じて投影レンズ6,7の焦点距離が変化する。すなわ
ち、円筒62,72に印加する電圧が大きくなるほど、
円筒62,72を通過する電子ビームBの速度が増加し
て投影レンズ6,7の焦点距離が長くなる。In the cylinders 62 and 72 of the projection lenses 6 and 7,
A voltage on the positive electrode side is applied from the CPU 10 via the interface 11 and the voltage amplifier 12, and the focal lengths of the projection lenses 6 and 7 change according to the applied voltage. That is, as the voltage applied to the cylinders 62 and 72 increases,
The velocity of the electron beam B passing through the cylinders 62, 72 increases, and the focal lengths of the projection lenses 6, 7 become longer.
【0015】CPU10はマイクロコンピュータおよび
その周辺機器を有するもので、不図示のメモリに書き込
まれる露光プログラムにしたがって露光装置の各部の動
作シーケンスを制御するとともに、露光プログラム上で
指定される副視野SFへ電子ビームBが到達するように
偏向器3への印加電圧を制御して電子ビームBの偏向方
向および偏向量を調節する。また、CPU10は指定さ
れた副視野SFに応じて円筒62,67への印加電圧を
制御する。The CPU 10 has a microcomputer and its peripherals, controls the operation sequence of each part of the exposure apparatus in accordance with an exposure program written in a memory (not shown), and sets the sub-field of view SF designated on the exposure program. The voltage applied to the deflector 3 is controlled so that the electron beam B reaches and the deflection direction and the deflection amount of the electron beam B are adjusted. Further, the CPU 10 controls the voltage applied to the cylinders 62 and 67 according to the designated sub-field of view SF.
【0016】CPU10のメモリには、偏向器3へ印加
すべき電圧をマスク5の副視野SF別に指示する第1の
データテーブルと、円筒62,72へ印加すべき電圧を
副視野SF別に指示する第2のデータテーブルとが格納
されている。第2のデータテーブルでは、副視野SFに
おけるパターンの充填率(副視野SF内の透過部5aの
面積の総和/副視野SFの面積)が大きいほど円筒6
2,72へ印加する電圧が小さくなる。図2の例であれ
ば、右側の副視野SFの方が左側の副視野SFよりもパ
ターン充填率が小さいので、右側の副視野SFに対応す
る円筒62,72への印加電圧の方が左側の副視野SF
に対応する円筒62,72への印加電圧よりも大きく指
定される。In the memory of the CPU 10, a first data table indicating the voltage to be applied to the deflector 3 for each sub-field of view SF of the mask 5, and the voltage to be applied to the cylinders 62 and 72 for each sub-field of view SF are indicated. And a second data table. In the second data table, the larger the filling rate of the pattern in the sub-field of view SF (total area of transmissive portions 5a in sub-field of view SF / area of sub-field of view SF), the larger the cylinder 6 is.
The voltage applied to 2, 72 becomes smaller. In the example of FIG. 2, since the pattern filling rate of the right sub-field of view SF is smaller than that of the left sub-field of view SF, the voltage applied to the cylinders 62 and 72 corresponding to the right sub-field of view SF is on the left side. Sub-field of view SF
Is specified to be larger than the applied voltage to the cylinders 62 and 72 corresponding to.
【0017】図3はCPU10で実行される各種の処理
のうち、特に偏向器3および投影レンズ6,7の円筒6
2,72への印加電圧の調節に係る処理手順を示すフロ
ーチャートである。露光装置全体の動作を指示する露光
プログラムによりマスク5の特定の副視野SFが電子ビ
ームによる照射対象として指定されると図示のプログラ
ムによる処理が開始される。まず、ステップS1では露
光プログラムにて指定された副視野SFを認識する。次
のステップS2では、指定された副視野SFに対応する
偏向器3への印加電圧を上述した第1のデータテーブル
により決定し、その結果を記憶する。続くステップS3
では指定された副視野SFに対応する円筒62,72へ
の印加電圧を上述した第2のデータテーブルにより決定
し、その結果を記憶する。そして、ステップS4ではス
テップS2,S3で決定した印加電圧に対応する信号を
インターフェース11へ並列に出力し、電圧増幅器12
により所定の電圧に変換して偏向器3、円筒62,72
へ印加する。ステップS4の処理後は、露光動作全般を
制御する露光プログラムに復帰し、指定された副視野S
Fへの露光を開始する。FIG. 3 shows various types of processing executed by the CPU 10, particularly the deflector 3 and the cylinder 6 of the projection lenses 6 and 7.
It is a flow chart which shows the processing procedure concerning adjustment of the applied voltage to 2,72. When a specific sub-field of view SF of the mask 5 is designated as an irradiation target by an electron beam by an exposure program that instructs the operation of the entire exposure apparatus, the processing by the illustrated program is started. First, in step S1, the sub-field of view SF designated by the exposure program is recognized. In the next step S2, the voltage applied to the deflector 3 corresponding to the designated sub-field of view SF is determined by the above-mentioned first data table, and the result is stored. Continuing step S3
Then, the applied voltage to the cylinders 62 and 72 corresponding to the designated sub-field of view SF is determined by the second data table described above, and the result is stored. Then, in step S4, a signal corresponding to the applied voltage determined in steps S2 and S3 is output in parallel to the interface 11, and the voltage amplifier 12
Is converted into a predetermined voltage by the deflector 3 and the cylinders 62 and 72.
Apply to. After the processing of step S4, the process returns to the exposure program that controls the overall exposure operation, and the designated sub-field of view S
Start exposure to F.
【0018】以上の処理によれば、マスク5の特定の副
視野SFが露光対象として指定されるつど、予め作成さ
れた第2のデータテーブルにしたがって円筒62,72
への印加電圧が調節されて投影レンズ6,7への焦点距
離が変化する。第2のデータテーブルでは、既述したよ
うにパターンの充填率が大きいほど円筒62,72への
印加電圧が小さく指定されるので、パターンの充填率が
大きい副視野SFでは投影レンズ6,7の焦点距離が相
対的に短く、充填率が小さい副視野SFでは投影レンズ
6,7の焦点距離が相対的に長くなる。According to the above processing, each time the specific sub-field of view SF of the mask 5 is designated as the exposure target, the cylinders 62, 72 are formed according to the second data table created in advance.
The voltage applied to the projection lenses 6 and 7 is adjusted to change the focal length. In the second data table, as described above, the larger the pattern filling rate is, the smaller the voltage applied to the cylinders 62 and 72 is specified. In the sub-field of view SF having a relatively short focal length and a small filling rate, the focal lengths of the projection lenses 6 and 7 are relatively long.
【0019】一方、電子銃1から副視野SFへ照射され
る電子ビームのビーム電流は一定であるため、マスク5
の透過部5aを通過する電子ビームのビーム電流はパタ
ーン充填率が大きいほど増加し、上述したの空間電荷
効果により電子ビームの焦点は遠方へ移動する。この空
間電荷効果による焦点の移動は上述した投影レンズ6,
7の焦点距離距離の変化によって相殺され、この結果、
ウエハW上での電子ビームのボケが抑制される。第2の
データテーブル上で指定する円筒62,72への印加電
圧を実験あるいは計算機シュミレーション等で精密に定
めれば、副視野SFの種類を問わず電子ビームのボケを
完全に防止することも可能である。したがって、電子銃
1から放出する電子ビームBのビーム電流を従来よりも
増加させ、副視野SFの露光時間を短縮してスループッ
トを大きく向上させることができる。なお、通常の露光
装置では、副視野SF毎の露光に先立って種々の段取が
行なわれるので、これらの間に図3の処理を行なえば、
副視野SF毎に焦点距離を調節しても露光前の段取に要
する時間は変らない。On the other hand, since the beam current of the electron beam emitted from the electron gun 1 to the sub-field of view SF is constant, the mask 5
The beam current of the electron beam passing through the transparent portion 5a increases as the pattern filling rate increases, and the focus of the electron beam moves far due to the space charge effect described above. The movement of the focus due to this space charge effect is caused by the above-mentioned projection lens 6,
Offset by a change in focal length of 7, resulting in
The blurring of the electron beam on the wafer W is suppressed. If the applied voltage to the cylinders 62 and 72 designated on the second data table is precisely determined by experiment or computer simulation, it is possible to completely prevent the electron beam from being blurred regardless of the type of the sub-field of view SF. Is. Therefore, the beam current of the electron beam B emitted from the electron gun 1 can be increased more than in the conventional case, the exposure time of the sub-field of view SF can be shortened, and the throughput can be greatly improved. Note that in a normal exposure apparatus, various setups are performed prior to the exposure for each sub-field of view SF, so if the processing of FIG.
Even if the focal length is adjusted for each sub-field of view SF, the time required for setup before exposure does not change.
【0020】また、実施例では投影レンズ6,7内に挿
入した円筒62,72への印加電圧を調節して静電的に
投影レンズ6,7の焦点距離を増減させるので、投影レ
ンズ6,7のコイル60,70への供給電流を変化させ
て焦点調節を行なう場合よりも遥かに短い時間で投影レ
ンズ6,7の焦点距離を調節できる。すなわち、コイル
60,70の供給電流を変化させて磁場そのものを調節
する場合には、コイル60,70を取り囲む強磁性体6
1,71の応答速度より速く磁場を変化させることがで
きず、投影レンズ6,7の焦点がコイル電流の変化に対
応した位置に整定するまでに相当の時間を要する。これ
に対して実施例では円筒62,72への印加電圧を変え
るだけなので、投影レンズ6,7の焦点が目標位置へ速
やかに移動する。また、コイル60,70は電子ビーム
を通過させる真空容器外へ設置されるので、コイル6
0,70による磁場が電子ビームの通過する真空領域内
に作用する過程で金属製の真空容器の壁に渦電流が流
れ、これによっても整定時間が長くなるが、円筒62,
72は真空容器中に置くことができるのでそのような待
ち時間は生じない。Further, in the embodiment, the voltage applied to the cylinders 62 and 72 inserted in the projection lenses 6 and 7 is adjusted to electrostatically increase or decrease the focal length of the projection lenses 6 and 7. The focal lengths of the projection lenses 6 and 7 can be adjusted in a much shorter time than in the case where focus adjustment is performed by changing the current supplied to the coils 60 and 70 of 7. That is, when the magnetic field itself is adjusted by changing the current supplied to the coils 60 and 70, the ferromagnetic material 6 surrounding the coils 60 and 70 is used.
It is not possible to change the magnetic field faster than the response speeds of 1 and 71, and it takes a considerable time for the focal points of the projection lenses 6 and 7 to settle at positions corresponding to changes in the coil current. On the other hand, in the embodiment, only the voltage applied to the cylinders 62 and 72 is changed, so that the focal points of the projection lenses 6 and 7 move quickly to the target position. Further, since the coils 60 and 70 are installed outside the vacuum container that allows the electron beam to pass therethrough, the coil 6
An eddy current flows through the wall of the metal vacuum container in the process in which the magnetic field of 0, 70 acts in the vacuum region where the electron beam passes, and this also increases the settling time, but the cylinder 62,
Since 72 can be placed in a vacuum vessel, such waiting time does not occur.
【0021】実施例では投影レンズ6,7の焦点距離を
副視野SF毎に指定する第2のデータテーブルを作成
し、副視野SFが指定されるつど第2のデータテーブル
を参照して焦点調節を行なったが、本発明はこのような
態様に限るものではなく、例えば副視野SFの設計デー
タからパターンの充填率を演算し、演算結果に対応して
焦点距離を求めるようにしてもよい。In the embodiment, a second data table that specifies the focal lengths of the projection lenses 6 and 7 for each sub-field of view SF is created, and the focus adjustment is performed by referring to the second data table each time the sub-field of view SF is specified. However, the present invention is not limited to such an aspect, and for example, the filling rate of the pattern may be calculated from the design data of the sub-field of view SF, and the focal length may be obtained corresponding to the calculation result.
【0022】以上の実施例と請求項との対応において、
マスク5の副視野SFがマスクの特定範囲を、マスク5
の透過部5aがマスクのパターンを、ウエハWが感光基
板を、CPU10および円筒62,72が焦点制御手段
を構成する。In the correspondence between the above embodiment and the claims,
The sub-field of view SF of the mask 5 covers a specific range of the mask
The transparent portion 5a constitutes a mask pattern, the wafer W constitutes a photosensitive substrate, and the CPU 10 and the cylinders 62 and 72 constitute focus control means.
【0023】[0023]
【発明の効果】以上説明したように、本発明では、マス
クのパターンを通過する荷電粒子線の空間電荷効果に起
因した焦点位置の変化と投影レンズの焦点距離の変化と
が相殺されるので、空間電荷効果による感光基板上での
荷電粒子線のボケを抑制しつつマスクへ照射する荷電粒
子線のビーム電流を増加させて露光時間を短縮し、スル
ープットを大きく向上させることができる。露光時間の
短縮によりレジストの熱膨張も抑制されて露光精度が大
きく向上する。請求項2の装置では、投影レンズの焦点
距離を変更する際の整定時間を短縮してスループットを
一層向上させることができる。As described above, according to the present invention, the change in the focal position due to the space charge effect of the charged particle beam passing through the mask pattern and the change in the focal length of the projection lens are canceled out. The exposure time can be shortened by increasing the beam current of the charged particle beam with which the mask is irradiated while suppressing the blurring of the charged particle beam on the photosensitive substrate due to the space charge effect, and the throughput can be greatly improved. By shortening the exposure time, the thermal expansion of the resist is suppressed and the exposure accuracy is greatly improved. In the apparatus of the second aspect, it is possible to shorten the settling time when changing the focal length of the projection lens and further improve the throughput.
【図1】本発明の一実施例における露光装置の概略構成
を示す図。FIG. 1 is a diagram showing a schematic configuration of an exposure apparatus according to an embodiment of the present invention.
【図2】図1のマスクの一部を拡大して示す図。FIG. 2 is an enlarged view showing a part of the mask shown in FIG.
【図3】図1のCPUにおける焦点制御手順を示すフロ
ーチャート。FIG. 3 is a flowchart showing a focus control procedure in the CPU of FIG.
1 電子銃 5 マスク 5a マスクの透過部 6,7 投影レンズ 10 CPU 60,70 投影レンズのコイル 62,72 投影レンズ内に挿入した円筒 B 電子ビーム SF マスクを分割した副視野 W ウエハ DESCRIPTION OF SYMBOLS 1 Electron gun 5 Mask 5a Transmission part of mask 6,7 Projection lens 10 CPU 60,70 Coil 62,72 of projection lens Cylindrical B electron beam SF inserted in the projection lens Subfield of view W mask Wafer
Claims (2)
時に照射し、当該特定範囲に形成されたパターンを投影
レンズを介して感光基板に転写する荷電粒子線露光装置
において、 前記マスク上の前記特定範囲における前記パターンの充
填率が大きいほど前記投影レンズの焦点距離が短くなる
ように当該投影レンズを制御する焦点制御手段を備える
ことを特徴とする荷電粒子線露光装置。1. A charged particle beam exposure apparatus which simultaneously irradiates a specific area of a mask with a charged particle beam and transfers a pattern formed in the specific area onto a photosensitive substrate through a projection lens. A charged particle beam exposure apparatus comprising: focus control means for controlling the projection lens such that the greater the filling rate of the pattern in the range is, the shorter the focal length of the projection lens is.
いて、 前記焦点制御手段は、前記投影レンズに挿入された非磁
性体製の円筒への印加電圧を調節して前記焦点距離を変
化させることを特徴とする荷電粒子線露光装置。2. The charged particle beam exposure apparatus according to claim 1, wherein the focus control unit changes the focal length by adjusting a voltage applied to a non-magnetic cylinder inserted in the projection lens. A charged particle beam exposure apparatus characterized by the above.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP5157488A JPH07135144A (en) | 1993-06-28 | 1993-06-28 | Charged particle beam aligner |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP5157488A JPH07135144A (en) | 1993-06-28 | 1993-06-28 | Charged particle beam aligner |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH07135144A true JPH07135144A (en) | 1995-05-23 |
Family
ID=15650784
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP5157488A Pending JPH07135144A (en) | 1993-06-28 | 1993-06-28 | Charged particle beam aligner |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH07135144A (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2006032202A (en) * | 2004-07-20 | 2006-02-02 | Hitachi High-Technologies Corp | Charged particle beam device |
-
1993
- 1993-06-28 JP JP5157488A patent/JPH07135144A/en active Pending
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2006032202A (en) * | 2004-07-20 | 2006-02-02 | Hitachi High-Technologies Corp | Charged particle beam device |
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