JP2006210459A - Charged particle beam exposure apparatus and method, and method of fabricating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance writing performance such as dimensional accuracy of a pattern by preventing the occurrence of such a state as a part of a beam is missed or a part of a beam is exposed during writing. <P>SOLUTION: In order to expose a desired pattern on a substrate using a charged particle beam, a blanking aperture 110 for shielding the charged particle beam, BA stages 401 and 402 for moving the blanking aperture 110 in a plane substantially perpendicular to the optical axis, and a means for varying the opening area of the blanking aperture 110 are provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a charged particle beam exposure apparatus such as an electron beam exposure apparatus or an ion beam exposure apparatus mainly used for exposure of a semiconductor integrated circuit or the like.

  A plurality of electron beams are irradiated onto the substrate to be exposed, the plurality of electron beams are deflected to scan the substrate, and the plurality of electron beams are individually turned on / off according to the pattern to be drawn, thereby drawing the pattern. A multi-beam electron beam exposure apparatus is disclosed in, for example, Japanese Patent Application Laid-Open No. 09-245708.

  In this example, it is required that the distribution centers of a plurality of electron beams at the pupil position of the optical system coincide with the centers of blanking apertures.

  An electron beam exposure apparatus that exposes a mask pattern onto an exposed substrate is described, for example, on pages 2840 to 2846 of JVSTB 1999.

Also in this example, it is required that the distribution centers of electron beams having various image heights coincide with each other in the pupil of the optical system.
JP 09-245708 A JVST B 1999, pages 2840 to 2846

  However, due to lens aberrations and adhesion of non-metal substances near the optical path of the charged particle beam, the charged particle beam is displaced at the pupil position of the optical system. Due to the positional deviation, a part of the beam is always missing during the drawing or a part of the beam is always exposed, and the drawing accuracy such as the pattern dimension accuracy deteriorates.

  An object of the present invention is to make a state in which a part of a beam is missing during drawing by matching the distribution center of electron beams having a plurality of or various image heights at the pupil position of an optical system with the center of a blanking aperture. It is to prevent a part of the beam from being exposed and improve drawing performance such as pattern dimension accuracy.

  The present invention has been made in view of the above-described conventional problems, and is a charged particle beam exposure apparatus that exposes a desired pattern on a substrate to be exposed using a charged particle beam, the charged particle beam being A blanking aperture for shielding, a moving means for moving the blanking aperture in a plane substantially perpendicular to the optical axis, and an opening variable means for changing the opening area of the blanking aperture. And

  The moving means measures, for example, a means for measuring a current amount of the charged particle beam on the substrate to be exposed that has passed through the blanking aperture, and measures a current amount of the charged particle beam on the substrate to be exposed. Means for controlling the amount and direction of movement of the blanking aperture based on the measurement result of the means for performing the above. Alternatively, the movement of the blanking aperture based on the measurement results of the means for measuring the current amount of the charged particle beam at the blanking aperture and the means for measuring the current amount of the charged particle beam at the blanking aperture. And means for controlling the amount and the moving direction.

  The aperture variable means includes, for example, a measurement result of a means for measuring a current amount of the charged particle beam on the substrate to be exposed and a means for measuring a current amount of the charged particle beam on the substrate to be exposed. And a means for adjusting an opening area of the blanking aperture based thereon. Alternatively, the opening of the blanking aperture based on the measurement results of the means for measuring the current amount of the charged particle beam at the blanking aperture and the means for measuring the current amount of the charged particle beam at the blanking aperture. And a means for adjusting the area.

  Further, the blanking apertures are arranged at a plurality of different positions in the optical axis direction, for example.

  The charged particle beam exposure method of the present invention is a charged particle beam exposure method for exposing a desired pattern on a substrate to be exposed using a charged particle beam, and a blanking aperture for shielding the charged particle beam. Moving in a plane substantially perpendicular to the optical axis, and adjusting the opening area of the blanking aperture.

  Furthermore, the device manufacturing method of the present invention comprises a step of exposing the substrate to be exposed using the charged particle beam exposure apparatus, and a step of developing the exposed substrate to be exposed. To do.

  According to the present invention, it is possible to provide a charged particle beam drawing apparatus having good drawing performance such as pattern dimension accuracy. Moreover, if a device is manufactured using this apparatus, a device with higher accuracy than before can be manufactured.

  A preferred embodiment for carrying out the present invention will be described in detail below with reference to the drawings, taking an example where a substrate to be exposed or an exposure target in a multi-beam type electron beam exposure apparatus is a wafer.

  FIG. 1 is a schematic diagram of a main part of a multi-beam electron beam exposure apparatus according to Embodiment 1 of the present invention. Reference numerals 101 to 109 denote multi-source modules that form a plurality of electron source images and emit an electron beam from the electron source images. In the case of FIG. ing.

  Reference numeral 101 denotes an electron source (crossover image) formed by the electron gun. The electron beam emitted from the electron source 101 becomes a substantially parallel electron beam by the condenser lens 102. Reference numeral 103 denotes an aperture array in which apertures are two-dimensionally arranged. Reference numeral 104 denotes a lens array in which electrostatic lenses having the same optical power are two-dimensionally arranged. Reference numerals 105, 106, 107, and 108 denote multi-deflector arrays formed by two-dimensionally arranging electrostatic deflectors that can be individually driven. Reference numeral 109 denotes a blanker array formed by two-dimensionally arranging electrostatic blankers that can be individually driven.

  Each function will be described with reference to FIG. The substantially parallel electron beam from the condenser lens 102 shown in FIG. 1 is divided into a plurality of electron beams by the aperture array 103. The divided electron beam forms an intermediate image 201 of the electron source 101 on the corresponding blanker of the blanker array 109 via the electrostatic lens of the corresponding lens array 104. At this time, the multi deflector arrays 105, 106, 107, and 108 individually adjust the position of the intermediate image 201 of the electron source formed on the blanker array 109 (position in the plane orthogonal to the optical axis).

  Further, since the electron beam deflected by the blanker array 109 is blocked by the blanking aperture 110 in FIG. 1, the wafer 120 is not irradiated. On the other hand, the electron beam that is not deflected by the blanker array 109 is not blocked by the blanking aperture 110 in FIG.

  Returning to FIG. 1, a plurality of intermediate images of the electron source formed by the multi-source module are projected onto the wafer 120 via the reduction projection system of the magnetic lenses 115, 116, 117, and 118. At this time, when a plurality of intermediate images are projected onto the wafer 120, the focal position can be adjusted by the dynamic focus lenses (electrostatic or magnetic field lenses) 111 and 112. Reference numerals 113 and 114 denote a main deflector and a sub deflector for deflecting each electron beam to a position to be exposed. 119 is a backscattered electron detector for measuring the position of each intermediate image of the electron source formed on the wafer 120. Reference numeral 121 denotes a wafer stage for moving the wafer. Reference numeral 122 denotes a mark for detecting the position and beam shape of the electron beam.

  Originally, in the blanking aperture located at the pupil of the reduction lens system, the positions of the plurality of electron beams coincide. However, when a non-metal substance adheres to a lens aberration or a device such as a multi-deflector array or a blanker array, as shown in FIG. 3, the electron beam is displaced at the blanking aperture position. In FIG. 3, reference numeral 301 denotes a blanking aperture, and reference numeral 302 denotes an electron beam at a position where it should originally be. Reference numeral 303 denotes an electron beam at a position deviated from the original position due to a lens aberration or a non-metal substance adhering to a device such as a multi-deflector array or a blanker array.

  Due to misalignment of the electron beam at the blanking aperture position, part of the beam is always missing during drawing, or part of the beam is always exposed, rendering accuracy such as pattern dimensional accuracy deteriorates. To do.

Hereinafter, a blanking aperture that is positioned at the pupil of the reduction lens system and shields the electron beam will be described.
As shown in FIG. 4, the blanking aperture includes two BA stages 401 and 402 and two openings 403 and 404, and the shapes of the openings 403 and 404 are polygons or ellipses. The blanking aperture is moved by moving the two BA stages 401 and 402 in the same direction in a plane perpendicular to the optical axis, and the two BA stages 401 and 402 are in a plane perpendicular to the optical axis. Change the opening size of the blanking aperture by moving in different directions.

Further, the blanking aperture may have a form as shown in FIG. The blanking aperture is moved by changing the size of the opening 507 by pushing the plates 501, 502, 503, 504, 505, and 506 in a circular shape and moving them on the stage.
Further, the blanking aperture may have a form as shown in FIG. In order to be able to select a desired opening size, a flat plate 604 having a plurality of openings 601, 602, and 603 having different diameters can be selected, and the desired opening size can be selected by translating the flat plate. It is configured.

  As shown in FIG. 7, the two BA stages 701 and 702 of the blanking aperture may be arranged at different positions in the optical axis direction, particularly at different pupil positions. 701 is one BA stage, and 702 is another BA stage.

  The direction and amount of movement of the blanking aperture are controlled by measuring the amount of electron beam current on the wafer stage. This will be described below.

  In FIG. 1, one or more electron detectors 119 capable of measuring the amount of electron beam current are arranged on a wafer stage 121. When the number of electron detectors 119 is smaller than the number of electron beams, the current amounts of a plurality of electron beams are measured while moving the wafer stage 121.

  If there is an electron beam that does not reach the desired current amount from the measured current amounts of the plurality of electron beams, the blanking aperture 110 moves in a direction in which the electron beam is not shielded by the blanking aperture 110. Further, the blanking aperture 110 is moved until all the measured current amounts of the plurality of electron beams are equal to or larger than a desired current amount. When moving the blanking aperture 110, the size of the blanking aperture 110 is set to a size sufficient to allow all electron beams to pass through.

The direction and amount of movement of the blanking aperture 110 may be controlled by measuring the amount of current flowing through the blanking aperture 110. When a plurality of electron beams are shielded by the blanking aperture 110, current flows through the blanking aperture 110, and therefore the blanking aperture 110 is moved in a direction such that the current value is equal to or less than a predetermined value.
The determination of the moving direction and the moving amount of the blanking aperture may be performed in a state where one electron beam is selected using the blanker array 109 or may be performed in a state where a plurality of electron beams are selected. .

Next, the size of the opening of the blanking aperture 110 is controlled by measuring the amount of current of the electron beam on the wafer stage 121. This will be described below.
The size of the opening of the blanking aperture 110 is set to a size that allows all beams to pass when the electron beam is on and shields all the beams when the electron beam is off.

  In this way, by setting the size of the opening of the blanking aperture 110 to a level that allows all beams to pass through, the on / off control of the electron beam can be performed at high speed, and pattern dimension accuracy and the like can be drawn. The on / off transition state of the electron beam that deteriorates the performance can be shortened as much as possible.

  In order for all the beams to pass when the electron beam is on, the size of the opening of the blanking aperture 110 is adjusted so that the current value measured using the electron detector 119 on the wafer stage 121 is maximized. In order to shield all the beams when the electron beam is off, the size of the opening of the blanking aperture 110 is set so that the current value measured using the electron detector 119 on the wafer stage 121 is not more than a predetermined value. To control.

The size of the opening of the blanking aperture 110 may be controlled by measuring the amount of current flowing through the blanking aperture 110. By setting the amount of current flowing through the blanking aperture 110 when the electron beam is on to be a predetermined value or less, and setting the amount of current flowing through the blanking aperture 110 when the electron beam is off to a maximum value, The size of the opening of the blanking aperture 110 is controlled.
Further, the size of the opening of the blanking aperture may be determined in a state where one electron beam is selected using the blanker array 109 or may be performed in a state where a plurality of electron beams are selected.

  As described above, the blanking aperture that shields the electron beam has a moving means that moves in a plane substantially perpendicular to the optical axis, and an opening variable means that changes the size of the opening. The center of the blanking aperture and the optical axis of the charged particle beam are made to substantially coincide with each other using the means and the movement amount control means, and the aperture of the blanking aperture is made to be all charged particle beams using the aperture variable means and the aperture diameter control means. It is possible to make it the last size that can pass.

The operation of the electron beam exposure apparatus of this embodiment will be described with reference to FIGS.
In (Step 81), the size of the blanking aperture 110 is set to a size that allows all electron beams to pass. After setting the size of the blanking aperture 110, the routine proceeds to step 82.

  In (Step 82), the current amount of all the electron beams is measured using the electron detector 119 on the wafer stage 121, and all the measured current amounts of the plurality of electron beams are equal to or greater than the desired current amount. In addition, the amount and direction of movement of the blanking aperture 110 are controlled. Alternatively, the amount of current flowing through the blanking aperture 110 is measured, and the amount of movement and the direction of movement of the blanking aperture 110 are controlled so that all of the measured current amounts of the plurality of electron beams are less than or equal to the desired amount of current. .

  At that time, the movement amount and the movement direction of the blanking aperture 110 are controlled so that the center of all electron beams becomes the center of the opening of the blanking aperture 110. After controlling the amount and direction of movement of the blanking aperture 110, the routine proceeds to step 83.

  In (Step 83), the blanking aperture 110 is moved based on the moving amount and moving direction of the blanking aperture 110 determined in Step 82. After the movement of the blanking aperture 110, the process proceeds to step 84.

  In step 84, all of the plurality of electron beams pass through the blanking aperture 110 from the amount of electron beam current measured by the electron detector 119 on the wafer stage 121 or the amount of current flowing through the blanking aperture 110. Judge whether or not. That is, when measured by the electron detector 119 on the wafer stage 121, whether or not all the measured current amounts of the plurality of electron beams are greater than or equal to a desired current amount, the amount of current flowing through the blanking aperture 110 is determined. When measured, it is determined whether or not all of the measured current amounts of the plurality of electron beams are equal to or less than a desired current amount.

  If all the plurality of electron beams have passed through the blanking aperture 110, the process proceeds to step 85. If all the plurality of electron beams have not passed through the blanking aperture 110, the process proceeds to step 82.

  In (Step 85), all electron beams are set off. That is, all the electron beams are shielded by the blanking aperture 110. After all the electron beams are set to OFF, the process proceeds to step 86.

  In (Step 86), the opening of the blanking aperture 110 is reduced by a predetermined value. At that time, the size of the opening of the blanking aperture 110 is changed while the position of the opening center of the blanking aperture 110 is maintained. After the opening of the blanking aperture 110 is reduced by a predetermined value, the routine proceeds to step 87.

  In step 87, all of the plurality of electron beams are shielded by the blanking aperture 110 from the amount of electron beam current measured by the electron detector 119 on the wafer stage 121 or the amount of current flowing through the blanking aperture 110. Judge whether or not. That is, when measured by the electron detector 119 on the wafer stage 121, whether or not all the measured current amounts of the plurality of electron beams are equal to or less than the desired current amount, the amount of current flowing through the blanking aperture 110 is determined. In the case of measurement, it is determined whether or not all of the measured current amounts of the plurality of electron beams are greater than or equal to a desired current amount. When all of the plurality of electron beams are shielded by the blanking aperture 110, the process is terminated. If all the plurality of electron beams are not shielded by the blanking aperture 110, the process proceeds to step 86.

  FIG. 9 is a schematic diagram of a main part of an electron beam exposure apparatus using a mask according to Embodiment 2 of the present invention. Reference numeral 901 denotes an electron source (crossover image) formed by the electron gun. The electron beam emitted from the electron source 901 becomes a substantially parallel illumination beam by the condenser lens 902 and illuminates the mask 904.

  In the illumination optical system that illuminates the mask 904, although not shown, an illumination beam shaping aperture, a blanking deflector, a blanking aperture, an illumination beam deflector, and the like are arranged. The illumination beam 903 shaped in the illumination optical system is sequentially scanned on the mask 904 to illuminate each subfield of the mask 904 within the field of the illumination optical system.

  The mask 904 has a number of subfields and is placed on a movable mask stage 905. By moving the mask stage 905 in the plane perpendicular to the optical axis, each subfield on the mask 904 extending over a wider range than the field of view of the illumination optical system is illuminated.

  Below the mask 904, electromagnetic lenses 906 and 907 and deflectors 908 to 910 and 911 to 913 used for aberration correction and image position adjustment are provided. The electron beam that has passed through one subfield of the mask 904 is imaged at a predetermined position on the wafer 914 by electromagnetic lenses 906 and 907 and deflectors 908 to 913. An appropriate resist is applied on the wafer 914, an electron beam dose is given on the resist, and the pattern on the mask 904 is reduced and transferred onto the wafer 914. Although not shown, the projection optical system is also provided with various aberration correction lenses and magnification / shape correction lenses.

  A crossover 915 is formed at a point that internally divides the mask 904 and the wafer 914 by a reduction ratio, and an aperture 916 is provided at the crossover position. The aperture 916 is for blocking the electron beam scattered by the non-pattern part of the mask 904 from reaching the wafer 914.

  The wafer 914 is placed on a wafer stage 917 that can move in the XY directions. By synchronously scanning the mask stage 905 and the wafer stage 917 in opposite directions, each part of the device pattern that extends beyond the field of the projection optical system can be sequentially exposed.

  Originally, in the aperture 916 positioned at the pupil of the projection optical system, the positions of the electron beams that have passed through the respective subfields of the mask 904 coincide with each other. However, due to lens aberration and adhesion of a non-metallic material on the mask 904, the electron beam is misaligned in the aperture 916.

  Then, due to the positional deviation of the electron beam in the aperture 916, a part of the electron beam is always missing during drawing or a part of the electron beam is always exposed, and each subfield of the mask 904 is exposed. The dose amount of the electron beam is different, and the drawing performance such as pattern dimensional accuracy deteriorates.

  The aperture 916 has the same form as that shown in FIGS. 3 to 6 of the first embodiment. When the projection optical system has two pupils, aperture stages may be arranged at different pupil positions.

  Further, the moving method, moving amount, and opening size of the aperture 916 are controlled by measuring the amount of current on the wafer stage 917 or the amount of current flowing through the aperture 916, as in the first embodiment.

Next, as a third embodiment, a device production method using the electron beam exposure apparatus described in the first or second embodiment will be described.
FIG. 10 shows a flow of manufacturing a microdevice (a semiconductor chip such as an IC or LSI, a liquid crystal panel, a CCD, a thin film magnetic head, a micromachine, etc.). In step 101 (circuit design), a semiconductor device circuit is designed. In step 102 (EB data conversion), exposure control data for the exposure apparatus is created based on the designed circuit pattern. On the other hand, in step 103 (wafer manufacture), a wafer is manufactured using a material such as silicon. Step 104 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by lithography using the wafer and the exposure apparatus to which the prepared exposure control data is input. The next step 105 (assembly) is called a post-process, and is a process of forming a semiconductor chip using the wafer produced in step 104, and is a process such as an assembly process (dicing, bonding), a packaging process (chip encapsulation), or the like. including. In step 106 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device manufactured in step 105 are performed. Through these steps, the semiconductor device is completed and shipped (step 107).

  FIG. 11 shows a detailed flow of the wafer process. In step 111 (oxidation), the wafer surface is oxidized. In step 112 (CVD), an insulating film is formed on the wafer surface. In step 113 (electrode formation), an electrode is formed on the wafer by vapor deposition. In step 114 (ion implantation), ions are implanted into the wafer. In step 115 (resist process), a photosensitive agent is applied to the wafer. In step 116 (exposure), the circuit pattern is printed onto the wafer by exposure using the exposure apparatus described above. In step 117 (development), the exposed wafer is developed. In step 118 (etching), portions other than the developed resist image are removed. In step 119 (resist stripping), the resist that has become unnecessary after etching is removed. By repeatedly performing these steps, multiple circuit patterns are formed on the wafer.

  By using the manufacturing method of this embodiment, a highly integrated semiconductor device can be manufactured with high pattern dimension accuracy.

It is sectional drawing for demonstrating the principal part outline of the electron beam exposure apparatus of a multi-beam system based on Example 1 of this invention. It is sectional drawing for demonstrating the function of the multi source module in FIG. It is a top view for demonstrating the position shift of an electron beam in the blanking aperture position based on Example 1 of this invention. It is a top view for demonstrating the structure of the blanking aperture based on Example 1 of this invention. It is a top view for demonstrating the structure of the blanking aperture based on the Example of this invention. It is a top view for demonstrating the structure of the blanking aperture based on the Example of this invention. It is sectional drawing for demonstrating arrange | positioning two BA stages in another pupil position about the blanking aperture based on the Example of this invention. It is a figure for demonstrating the operation | movement flow of a blanking aperture in the electron beam exposure apparatus of Example 1 of this invention. It is sectional drawing for demonstrating the principal part outline of the electron beam exposure apparatus using the mask based on Example 2 of this invention. It is a figure for demonstrating the manufacturing flow of a microdevice based on Example 3 of this invention. It is a figure for demonstrating the wafer process in FIG.

Explanation of symbols

101: Electron source (crossover image)
102: condenser lens 103: aperture array 104: lens array 105: multi-deflector array 106: multi-deflector array 107: multi-deflector array 108: multi-deflector array 109: blanker array 110: blanking aperture 111: dynamic focus lens 112: Dynamic focus lens 113: Main deflector 114: Sub deflector 115: Magnetic lens 116: Magnetic lens 117: Magnetic lens 118: Magnetic lens 119: Reflected electron detector 120: Wafer 121: Wafer stage 122: Mark 201: Electron Source intermediate image 301: Blanking aperture 302: Original electron beam 303: Original electron beam position 303: Original beam position shifted from original position 401: BA stage 402: BA stage 40 : Opening 404: Opening 501: Plate 502 for controlling the size of the opening 502: Plate for controlling the size of the opening 503: Plate for controlling the size of the opening 504: Plate for controlling the size of the opening 505: Size of the opening Plate 506 for controlling the thickness: Plate 507 for controlling the size of the opening 507: Opening 601: Opening with different size 602: Opening with different size 603: Opening with different size 604: Flat plate 701 with a plurality of openings Stage 702: BA stage 901: Electron source (crossover image)
902: condenser lens 903: illumination beam 904: mask 905: mask stage 906: electromagnetic lens 907: electromagnetic lens 908: deflector 909: deflector 910: deflector 911: deflector 912: deflector 913: deflector 914: wafer 915: Crossover 916: Aperture 917: Wafer stage

Claims (8)

A charged particle beam exposure apparatus that exposes a desired pattern on a substrate to be exposed using a charged particle beam,
A blanking aperture for shielding the charged particle beam;
Moving means for moving the blanking aperture in a plane substantially perpendicular to the optical axis;
Opening variable means for changing the opening area of the blanking aperture;
A charged particle beam exposure apparatus comprising: The moving means measures a current amount of the charged particle beam on the exposed substrate that has passed through the blanking aperture; and
Means for controlling the amount and direction of movement of the blanking aperture based on the measurement result of the means for measuring the amount of current of the charged particle beam on the substrate to be exposed;
The charged particle beam exposure apparatus according to claim 1, comprising: The moving means includes means for measuring a current amount of the charged particle beam at the blanking aperture;
Means for controlling the amount and direction of movement of the blanking aperture based on the measurement result of the means for measuring the amount of current of the charged particle beam at the blanking aperture;
The charged particle beam exposure apparatus according to claim 1, comprising: The aperture varying means; means for measuring the amount of current of the charged particle beam on the substrate to be exposed;
Means for adjusting an opening area of the blanking aperture based on a measurement result of a means for measuring a current amount of the charged particle beam on the substrate to be exposed;
The charged particle beam exposure apparatus according to claim 2, wherein: The aperture variable means is means for measuring the amount of current of the charged particle beam at the blanking aperture;
Means for adjusting the opening area of the blanking aperture based on the measurement result of the means for measuring the amount of current of the charged particle beam at the blanking aperture;
The charged particle beam exposure apparatus according to claim 2, wherein:   6. The charged particle beam exposure apparatus according to claim 1, wherein the blanking apertures are arranged at a plurality of different positions in the optical axis direction. A charged particle beam exposure method for exposing a desired pattern on a substrate to be exposed using a charged particle beam,
Moving a blanking aperture for shielding the charged particle beam in a plane substantially perpendicular to the optical axis;
Adjusting the opening area of the blanking aperture;
A charged particle beam exposure method comprising: A step of exposing the substrate to be exposed using the charged particle beam exposure apparatus according to claim 1, a step of developing the exposed substrate to be exposed;
A device manufacturing method comprising:

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