US20090135481A1 - Polarizer, projection lens system, exposure apparatus and exposing method - Google Patents
Polarizer, projection lens system, exposure apparatus and exposing method Download PDFInfo
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- US20090135481A1 US20090135481A1 US12/359,673 US35967309A US2009135481A1 US 20090135481 A1 US20090135481 A1 US 20090135481A1 US 35967309 A US35967309 A US 35967309A US 2009135481 A1 US2009135481 A1 US 2009135481A1
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- light
- polarizer
- polarized light
- amplitude
- photoresist
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B27/00—Photographic printing apparatus
- G03B27/72—Controlling or varying light intensity, spectral composition, or exposure time in photographic printing apparatus
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/70—Microphotolithographic exposure; Apparatus therefor
- G03F7/70216—Mask projection systems
- G03F7/70308—Optical correction elements, filters or phase plates for manipulating imaging light, e.g. intensity, wavelength, polarisation, phase or image shift
Definitions
- the present invention relates to a technique for manufacturing a semiconductor device, and more particularly to a technique for exposure.
- NA numerical aperture
- Optical systems of usual exposure apparatuses have not been able to control polarization of diffracted light generated through a mask pattern, so that polarized light incident on a photoresist includes p-polarized light and s-polarized light in an even ratio.
- NA the angle of incidence on a target of exposure, i.e., a photoresist increases as described above, causing the ratio of p-polarized light and s-polarized light incident on the photoresist to vary.
- the contrast of an optical image differs between p-polarized light and s-polarized light, the contrast of an optical image generated by composition of p-polarized light and s-polarized light is degraded. Then, improvement in the degree of resolution cannot be expected even where NA is increased.
- a polarizer includes an even number of regions arranged adjacently to one another around a center. Directions of amplitude of light passing through the even number of regions distribute in the form of a regular polygon with an even number of members.
- the polarizer includes a plurality of transmission regions having a common center. Directions of amplitude of light passing through the plurality of regions distribute concentrically.
- the polarizer is disposed with its center lying on the center of the surface of the pupil of a projection lens system in an exposure apparatus, thereby transmitting s-polarized light of illumination light in the exposure apparatus while cutting off p-polarized light.
- exposure using light which has passed through the polarizer can improve the contrast of an optical image, and hence, resolution characteristics can be improved.
- a projection lens system employs the polarizer as a pupil filter.
- an exposure apparatus employs the projection lens system.
- an exposure method uses a mask with a light shielding portion and a pupil filter.
- a direction in which the light shielding portion extends is in parallel to a direction of amplitude of polarized light transmitted through the pupil filter.
- S-polarized light of illumination light is transmitted at exposure, while p-polarized light is cut off. Therefore, exposure using light which has passed through the polarizer can improve the contrast of an optical image, and hence, resolution characteristics can be improved.
- FIG. 1 shows an optical system of a projection exposure apparatus to which the present invention is applicable
- FIGS. 2 and 3 show the direction of amplitude of incident light
- FIG. 4 is a graph showing the reflectance of incident light
- FIG. 5 is a graph showing the light intensity in a photoresist
- FIG. 6 conceptually shows the behavior of light transmitted through a mask
- FIG. 7 conceptually shows positions where light passes through the surface of pupil
- FIG. 8 shows the characteristics of a polarizer according to a first preferred embodiment of the present invention
- FIGS. 9 to 11 show the characteristics of a polarizer according to a second preferred embodiment of the invention.
- FIGS. 12 and 13 show the characteristics of a polarizer according to a third preferred embodiment of the invention.
- FIGS. 14 to 16 show the characteristics of a polarizer according to a fourth preferred embodiment of the invention.
- FIG. 1 shows an optical system of a projection exposure apparatus to which the present invention is applicable. Illumination light emanated from a lamp house 11 is reflected off a mirror 12 , and passes through a fly eye lens 13 , an aperture member 14 , a relay lens 15 A and a blind 16 in this order, and is further reflected off a mirror 17 .
- the fly eye lens 13 is divided into a plurality of lens regions 13 a, and light emitted from the respective lens regions 13 a pass through an opening of the aperture member 14 .
- a photomask 18 On the surface of a photomask 18 , the light rays from the individual lens regions 13 a are laid on top of one another, which means the lens regions 13 a contribute to uniform illumination.
- the illumination light reflected off the mirror 17 reaches the photomask 18 with a circuit pattern formed thereon, through a condenser lens 15 B.
- the light which has passed through the photomask 18 (including diffracted light) passes through a projection lens system 19 to reach a wafer 20 .
- a photoresist not shown is provided on a surface of the wafer 20 that faces the projection lens system 19 and is exposed to the illumination light which has passed through the projection lens system 19 .
- the projection lens system 19 includes an aperture stop 22 , and a polarizer 21 for transmitting s-polarized light and cutting off p-polarized light is provided as a pupil filter on the surface of the pupil of the projection lens system 19 . Advantages of transmitting s-polarized light in the present invention will be discussed now.
- FIGS. 2 and 3 schematically show the directions of amplitude J of light in the case where incident light Q incident on a target is p-polarized light and s-polarized light, respectively.
- the directions of amplitude J of light are in parallel to the plane decided by the direction of the normal R to the target and the direction of the incident light Q, as shown in FIG. 2 .
- the directions of amplitude J of light are perpendicular to that plane, as shown in FIG. 3 .
- FIG. 4 is a graph showing the reflectance of incident light Q where a target is a photoresist.
- the angle of incidence ⁇ made by the direction of the normal R and the direction of the incident light Q is plotted on the horizontal axis, and the reflectance is plotted on the vertical axis.
- Dependence of the reflectance on the angle of incidence ⁇ differs between s-polarized light and p-polarized light. Particularly, the reflectance of p-polarized light greatly depends on the angle of incidence ⁇ . As NA increases, the angle of incidence ⁇ has a wider distribution. From this point of view, it is preferable to adopt s-polarized light for exposure.
- FIG. 5 is a graph showing the light intensity of an optical image in a photoresist.
- NA shall be 0.707
- the photoresist shall have an index of refraction of 1.5.
- S-polarized light has a steeper distribution than p-polarized light, and also from this point of view, it is preferable to adopt s-polarized light for exposure.
- FIG. 6 conceptually shows the behavior of light transmitted through the photomask 18 .
- diffracted light is generated in addition to zero-order diffracted light L 0 that has not been diffracted.
- FIG. 2 only shows first-order diffracted light L 1 primarily diffracted. The zero-order diffracted light L 0 and first-order diffracted light L 1 pass through the surface of the pupil 22 a to reach the photoresist on the wafer 20 .
- FIG. 7 conceptually shows positions where light passes through the surface of the pupil 22 a.
- FIG. 7 only shows diffracted light of only zero and first orders.
- the center 22 b of the surface of the pupil 22 a, a position P 0 through which zero-order diffracted light passes and a position P 1 through which first-order diffracted light passes lie on a straight line M. Diffracted light of subsequent orders also lies on the same straight line M.
- the polarizer 21 may only polarize light such that the directions of polarization are distributed concentrically around the center 22 b.
- FIG. 8 schematically shows the directions of amplitude J of polarized light passing through the polarizer 21 .
- the directions of amplitude J are concentric with respect to a position D.
- a plurality of transmission regions commonly centering at the position D are provided, and the directions of amplitude of light passing through these regions distribute concentrically.
- a polyvinyl alcohol film is dyed with and adsorbs iodine or organic dye and the film is drawn, so that a filter for transmitting polarized light traveling in a predetermined direction is generated (see e.g., aforementioned “Polarizing & Retardation Films”), and the filter thus generated is drawn isotropically with respect to its center.
- the polarizer 21 is thereby manufactured.
- the polarizer 21 is disposed on the surface of the pupil 22 a such that the position D lies exactly on the center 22 b.
- the rays of luminous flux of illumination light which have passed through the polarizer 21 are converged onto the wafer 20 with concentric planes of polarization with respect to the optical axis. That is, the illumination light is incident on the photoresist in the form of s-polarized light.
- the illumination light is incident on the photoresist on the wafer 20 in the form of s-polarized light in the projection lens system 19 , so that the amount of light entering the photoresist is less likely to depend upon the angle of incidence ⁇ .
- This can reduce variations in exposure characteristics of an exposure apparatus, even when an increase in NA of the projection lens system 19 widens the range of distribution of the angle of incidence ⁇ . Further, an optical image in the photoresist becomes steeper to improve its contrast, which therefore improves resolution characteristics.
- FIG. 9 illustrates a pattern on the photomask 18 .
- a plurality of light shielding portions 18 a extending in one direction are arranged at intervals in parallel to one another. Light incident on the photomask 18 passes through the intervals, while the light shielding portions 18 a shield the incident light.
- FIG. 10 schematically shows the behavior of diffracted light generated by the photomask 18 , seen in a direction parallel to that in which the light shielding portions 18 a extend.
- Incident light Li after passing through the intervals between the light shielding portions 18 a, is split into zero-order diffracted light L 0 and first-order diffracted light L 1 (or higher-order diffracted light). Since the light shielding portions 18 a extend in one direction, the diffracted light has the direction of polarization having a component parallel to that of the extending direction of the light shielding portions 18 a except at the ends of the light shielding portions 18 a in its extending direction.
- FIG. 9 schematically shows the directions of amplitude J of polarized light passing through the polarizer 21 .
- the directions of amplitude J of polarized light are aligned in one direction.
- Disposing the polarizer 21 on the surface of the pupil 22 a ( FIG. 6 ) such that the directions of amplitude of polarized light passing through the polarizer 21 are in parallel to the extending direction of the light shielding portions 18 a can achieve the same effects as in the first preferred embodiment as to exposure using the light shielding portions 18 a.
- the effects of the present embodiment become more apparent as the light shielding portions 18 a extending in one direction occupy a larger area on the photomask 18 .
- the polarizer 21 that makes the directions of amplitude of light passing therethrough concentric, such as that shown in FIG. 8 , by way of example, in the first preferred embodiment.
- FIG. 12 schematically shows the directions of amplitude J 1 and J 2 of light passing through the polarizer 21 according to the present embodiment.
- the polarizer 21 is equally divided in to four regions S 1 to S 4 centering at a position D.
- the direction of amplitude J 1 of polarized light passing through the regions S 1 and S 3 facing each other and the direction of amplitude J 2 of polarized light passing through the regions S 2 and S 4 facing each other are perpendicular to each other.
- FIG. 13 schematically shows the directions of amplitude J 1 to J 4 of polarized light passing through the polarizer 21 according to the present embodiment.
- the polarizer 21 is equally divided into eight regions S 11 to S 18 around the position D.
- the direction of amplitude J 11 of polarized light passing through the regions S 11 and S 15 facing each other crosses the direction of amplitude J 12 of polarized light passing through the regions S 12 and S 16 facing each other at 45 degrees.
- the direction of amplitude J 13 of polarized light passing through the regions S 13 and S 17 facing each other crosses the direction of amplitude J 12 at 45 degrees.
- the direction of amplitude J 14 of polarized light passing through the regions S 14 and S 18 facing each other crosses the direction of amplitude J 13 at 45 degrees.
- the directions of amplitude J 11 and J 14 cross each other at 45 degrees.
- the number of directions of amplitude of polarized light passing through the polarizer 21 is N and a minimum positive angle made by the respective directions of amplitude is (360/2N) degrees.
- the polarizer 21 is equally divided into 2N regions, and polarized light passing through regions facing each other has the same direction of amplitude. That is, distributions of the directions of polarized light passing through the polarizer 21 form a regular polygon with 2N members.
- FIG. 14 schematically shows the directions of amplitude J of polarized light passing through the polarizer 21 according to the present embodiment.
- the polarizer 21 has a ring-shaped region S 0 centering at the position D.
- the region S 0 is interposed between two circles concentric with respect to the position D. Selection of polarized light is not conducted in the range surrounded by the region S 0 , but incident light is transmitted.
- the directions of amplitude J of polarized light are concentric with respect to the position D, similarly to the directions shown in FIG. 8 .
- the polarizer 21 is disposed on the surface of the pupil 22 a such that the position D lies exactly on the center 22 b.
- the polarizer 21 may consist of the region S 0 alone.
- the angle of incidence ⁇ is about 40 degrees or smaller
- a difference in reflectivity between s-polarized light and p-polarized light increases with an increase in the angle of incidence ⁇ .
- p-polarized light resulting from incident light having a great angle of incidence may be limitedly cut off.
- the region S 0 shown in FIG. 14 is a peripheral portion with respect to the center D, where the angle of incidence is great. Therefore, the use of the polarizer 21 according to the present embodiment can improve the contrast of illumination light made incident at such an angle that resolution characteristics significantly degrade, similarly to the first preferred embodiment.
- FIGS. 15 and 16 each schematically show the directions of amplitude of polarized light passing through another type of polarizer 21 according to the present embodiment.
- FIG. 15 shows the structure in which the regions S 1 to S 4 of the polarizer 21 shown in FIG. 12 are transformed into regions S 21 to S 24 limited in a range at a certain distance from the center D.
- FIG. 16 shows the structure in which the regions S 11 to S 18 are transformed into regions S 31 to S 38 limited in a range at a certain distance from the center D.
Abstract
The directions of amplitude of polarized light passing through a polarizer are concentric around a position. The polarizer is disposed on the surface of a pupil such that the position lies exactly on the center of the surface of the pupil. Rays of luminous flux of illumination light converted into polarized light by the polarizer are converged onto a wafer with concentric planes of polarization with respect to an optical axis. The illumination light is therefore incident on a photoresist as s-polarized light. Thus, the amount of light entering the photoresist is less likely to depend upon the angle of incidence. Consequently, the contrast of an optical image formed in the photoresist is improved, and hence, resolution characteristics are improved.
Description
- This application is a Divisional of U.S. application Ser. No. 10/883,007, filed Jul. 2, 2004, claiming priority of Japanese Application No. 2003-190205, filed Jul. 2, 2003, the entire contents of each of which are hereby incorporated by reference.
- 1. Field of the Invention
- The present invention relates to a technique for manufacturing a semiconductor device, and more particularly to a technique for exposure.
- 2. Description of the Background Art
- Semiconductor devices are continuously becoming miniaturized, and the numerical aperture (NA) of exposure apparatuses is being increased for further miniaturization.
- However, as NA is getting higher, the angle of incidence on a target of exposure, e.g., a photoresist increases, which causes the effects of polarization which have been neglected to become evident. This causes degradation in imaging characteristics in the photoresist. Such circumstances are introduced in “Challenges in high NA, polarization, and photoresists” by Bruce W. Smith, et al., SPIE 2002, 4691-2, pp. 11-24. The following documents are related to the present invention: “Polarizing & Retardation Films” retrieved on May 15, 2003 from the Nitto Denko homepage <URL:http://www.nitto.co.jp/product/industry/electronics/output/lcds/polar/index.html>; Japanese Patent Application Laid-Open No. 5-226225 (1993); and Japanese Patent Application Laid-Open No. 2001-185476.
- Optical systems of usual exposure apparatuses have not been able to control polarization of diffracted light generated through a mask pattern, so that polarized light incident on a photoresist includes p-polarized light and s-polarized light in an even ratio. With an increase in NA of exposure apparatuses, the angle of incidence on a target of exposure, i.e., a photoresist increases as described above, causing the ratio of p-polarized light and s-polarized light incident on the photoresist to vary. Further, since the contrast of an optical image differs between p-polarized light and s-polarized light, the contrast of an optical image generated by composition of p-polarized light and s-polarized light is degraded. Then, improvement in the degree of resolution cannot be expected even where NA is increased.
- It is an object of the present invention to improve the contrast of an optical image generated in a photoresist, and therefore to improve resolution characteristics.
- According to the present invention, a polarizer includes an even number of regions arranged adjacently to one another around a center. Directions of amplitude of light passing through the even number of regions distribute in the form of a regular polygon with an even number of members. Alternatively, the polarizer includes a plurality of transmission regions having a common center. Directions of amplitude of light passing through the plurality of regions distribute concentrically.
- The polarizer is disposed with its center lying on the center of the surface of the pupil of a projection lens system in an exposure apparatus, thereby transmitting s-polarized light of illumination light in the exposure apparatus while cutting off p-polarized light. Thus, exposure using light which has passed through the polarizer can improve the contrast of an optical image, and hence, resolution characteristics can be improved.
- According to the present invention, a projection lens system employs the polarizer as a pupil filter.
- Therefore, variations in exposure characteristics of an exposure apparatus can be reduced, even when an increase in the numerical aperture of the projection lens system widens the range of distributions of the angle of incidence.
- According to the present invention, an exposure apparatus employs the projection lens system.
- Therefore, exposure using s-polarized light of illumination light can improve the contrast of an optical image, and hence, resolution characteristics can be improved.
- According to the present invention, an exposure method uses a mask with a light shielding portion and a pupil filter. A direction in which the light shielding portion extends is in parallel to a direction of amplitude of polarized light transmitted through the pupil filter.
- S-polarized light of illumination light is transmitted at exposure, while p-polarized light is cut off. Therefore, exposure using light which has passed through the polarizer can improve the contrast of an optical image, and hence, resolution characteristics can be improved.
- These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
-
FIG. 1 shows an optical system of a projection exposure apparatus to which the present invention is applicable; -
FIGS. 2 and 3 show the direction of amplitude of incident light; -
FIG. 4 is a graph showing the reflectance of incident light; -
FIG. 5 is a graph showing the light intensity in a photoresist; -
FIG. 6 conceptually shows the behavior of light transmitted through a mask; -
FIG. 7 conceptually shows positions where light passes through the surface of pupil; -
FIG. 8 shows the characteristics of a polarizer according to a first preferred embodiment of the present invention; -
FIGS. 9 to 11 show the characteristics of a polarizer according to a second preferred embodiment of the invention; -
FIGS. 12 and 13 show the characteristics of a polarizer according to a third preferred embodiment of the invention; and -
FIGS. 14 to 16 show the characteristics of a polarizer according to a fourth preferred embodiment of the invention. -
FIG. 1 shows an optical system of a projection exposure apparatus to which the present invention is applicable. Illumination light emanated from alamp house 11 is reflected off amirror 12, and passes through afly eye lens 13, anaperture member 14, arelay lens 15A and a blind 16 in this order, and is further reflected off amirror 17. - The
fly eye lens 13 is divided into a plurality of lens regions 13 a, and light emitted from the respective lens regions 13 a pass through an opening of theaperture member 14. On the surface of aphotomask 18, the light rays from the individual lens regions 13 a are laid on top of one another, which means the lens regions 13 a contribute to uniform illumination. - The illumination light reflected off the
mirror 17 reaches thephotomask 18 with a circuit pattern formed thereon, through acondenser lens 15B. The light which has passed through the photomask 18 (including diffracted light) passes through aprojection lens system 19 to reach awafer 20. A photoresist not shown is provided on a surface of thewafer 20 that faces theprojection lens system 19 and is exposed to the illumination light which has passed through theprojection lens system 19. - The
projection lens system 19 includes anaperture stop 22, and apolarizer 21 for transmitting s-polarized light and cutting off p-polarized light is provided as a pupil filter on the surface of the pupil of theprojection lens system 19. Advantages of transmitting s-polarized light in the present invention will be discussed now. -
FIGS. 2 and 3 schematically show the directions of amplitude J of light in the case where incident light Q incident on a target is p-polarized light and s-polarized light, respectively. When the incident light Q is p-polarized light, the directions of amplitude J of light are in parallel to the plane decided by the direction of the normal R to the target and the direction of the incident light Q, as shown inFIG. 2 . When the incident light Q is s-polarized light, the directions of amplitude J of light are perpendicular to that plane, as shown inFIG. 3 . -
FIG. 4 is a graph showing the reflectance of incident light Q where a target is a photoresist. The angle of incidence θ made by the direction of the normal R and the direction of the incident light Q is plotted on the horizontal axis, and the reflectance is plotted on the vertical axis. Dependence of the reflectance on the angle of incidence θ differs between s-polarized light and p-polarized light. Particularly, the reflectance of p-polarized light greatly depends on the angle of incidence θ. As NA increases, the angle of incidence θ has a wider distribution. From this point of view, it is preferable to adopt s-polarized light for exposure. -
FIG. 5 is a graph showing the light intensity of an optical image in a photoresist. Here, NA shall be 0.707, and the photoresist shall have an index of refraction of 1.5. Such intensity distributions result from interference of light that enters the photoresist. S-polarized light has a steeper distribution than p-polarized light, and also from this point of view, it is preferable to adopt s-polarized light for exposure. - Next, a desirable structure for the
polarizer 21 to transmit s-polarized light while cutting off p-polarized light will be discussed. -
FIG. 6 conceptually shows the behavior of light transmitted through thephotomask 18. At the time when incident light Li incident on thephotomask 18 passes through the edge of the pattern formed on thephotomask 18, diffracted light is generated in addition to zero-order diffracted light L0 that has not been diffracted.FIG. 2 only shows first-order diffracted light L1 primarily diffracted. The zero-order diffracted light L0 and first-order diffracted light L1 pass through the surface of the pupil 22 a to reach the photoresist on thewafer 20. -
FIG. 7 conceptually shows positions where light passes through the surface of the pupil 22 a.FIG. 7 only shows diffracted light of only zero and first orders. Thecenter 22 b of the surface of the pupil 22 a, a position P0 through which zero-order diffracted light passes and a position P1 through which first-order diffracted light passes lie on a straight line M. Diffracted light of subsequent orders also lies on the same straight line M. - Therefore, in order to make light transmitted through the polarizer 21 s-polarized light, only polarized light that is perpendicular to lines passing through the
center 22 b may be passed. For instance, thepolarizer 21 may only polarize light such that the directions of polarization are distributed concentrically around thecenter 22 b. -
FIG. 8 schematically shows the directions of amplitude J of polarized light passing through thepolarizer 21. The directions of amplitude J are concentric with respect to a position D. This can be said that a plurality of transmission regions commonly centering at the position D are provided, and the directions of amplitude of light passing through these regions distribute concentrically. For instance, a polyvinyl alcohol film is dyed with and adsorbs iodine or organic dye and the film is drawn, so that a filter for transmitting polarized light traveling in a predetermined direction is generated (see e.g., aforementioned “Polarizing & Retardation Films”), and the filter thus generated is drawn isotropically with respect to its center. Thepolarizer 21 is thereby manufactured. - The
polarizer 21 is disposed on the surface of the pupil 22 a such that the position D lies exactly on thecenter 22 b. The rays of luminous flux of illumination light which have passed through thepolarizer 21 are converged onto thewafer 20 with concentric planes of polarization with respect to the optical axis. That is, the illumination light is incident on the photoresist in the form of s-polarized light. - Through the use of
such polarizer 21, the illumination light is incident on the photoresist on thewafer 20 in the form of s-polarized light in theprojection lens system 19, so that the amount of light entering the photoresist is less likely to depend upon the angle of incidence θ. This can reduce variations in exposure characteristics of an exposure apparatus, even when an increase in NA of theprojection lens system 19 widens the range of distribution of the angle of incidence θ. Further, an optical image in the photoresist becomes steeper to improve its contrast, which therefore improves resolution characteristics. - In the present embodiment, another mode of the
polarizer 21 will be described, by way of example.FIG. 9 illustrates a pattern on thephotomask 18. In the pattern, a plurality of light shielding portions 18 a extending in one direction are arranged at intervals in parallel to one another. Light incident on thephotomask 18 passes through the intervals, while the light shielding portions 18 a shield the incident light. -
FIG. 10 schematically shows the behavior of diffracted light generated by thephotomask 18, seen in a direction parallel to that in which the light shielding portions 18 a extend. - Incident light Li, after passing through the intervals between the light shielding portions 18 a, is split into zero-order diffracted light L0 and first-order diffracted light L1 (or higher-order diffracted light). Since the light shielding portions 18 a extend in one direction, the diffracted light has the direction of polarization having a component parallel to that of the extending direction of the light shielding portions 18 a except at the ends of the light shielding portions 18 a in its extending direction.
- Therefore, as shown in
FIG. 9 , in exposure using the light shielding portions 18 a extending in one direction, causing thepolarizer 21 to transmit only polarized light traveling in the extending direction of the light shielding portions 18 a allows s-polarized light to be transmitted.FIG. 11 schematically shows the directions of amplitude J of polarized light passing through thepolarizer 21. The directions of amplitude J of polarized light are aligned in one direction. - Disposing the
polarizer 21 on the surface of the pupil 22 a (FIG. 6 ) such that the directions of amplitude of polarized light passing through thepolarizer 21 are in parallel to the extending direction of the light shielding portions 18 a can achieve the same effects as in the first preferred embodiment as to exposure using the light shielding portions 18 a. - The effects of the present embodiment become more apparent as the light shielding portions 18 a extending in one direction occupy a larger area on the
photomask 18. However, in the case where the pattern on thephotomask 18 extends in various directions, it is preferable to adopt thepolarizer 21 that makes the directions of amplitude of light passing therethrough concentric, such as that shown inFIG. 8 , by way of example, in the first preferred embodiment. -
FIG. 12 schematically shows the directions of amplitude J1 and J2 of light passing through thepolarizer 21 according to the present embodiment. Thepolarizer 21 is equally divided in to four regions S1 to S4 centering at a position D. The direction of amplitude J1 of polarized light passing through the regions S1 and S3 facing each other and the direction of amplitude J2 of polarized light passing through the regions S2 and S4 facing each other are perpendicular to each other. - Therefore, where there exist two pairs of light shielding portions in the pattern on the
photomask 18, each pair extending in one direction, and the extending directions of the two pairs cross each other at 90 (=360/4) degrees, the same effects as in the second preferred embodiment can be achieved. When disposing thepolarizer 21 on the surface of the pupil 22 a (FIG. 6 ), it is preferable that the directions of amplitude J1 and J2 and the extending directions of the two pairs of light shielding portions match, respectively. -
FIG. 13 schematically shows the directions of amplitude J1 to J4 of polarized light passing through thepolarizer 21 according to the present embodiment. Thepolarizer 21 is equally divided into eight regions S11 to S18 around the position D. The direction of amplitude J11 of polarized light passing through the regions S11 and S15 facing each other crosses the direction of amplitude J12 of polarized light passing through the regions S12 and S16 facing each other at 45 degrees. The direction of amplitude J13 of polarized light passing through the regions S13 and S17 facing each other crosses the direction of amplitude J12 at 45 degrees. The direction of amplitude J14 of polarized light passing through the regions S14 and S18 facing each other crosses the direction of amplitude J13 at 45 degrees. The directions of amplitude J11 and J14 cross each other at 45 degrees. - Therefore, where there exist four pairs of light shielding portions in the pattern on the
photomask 18, each pair extending in one direction, and the extending directions of the four pairs cross one another at 45 (=360/8) degrees, the same effects as in the second preferred embodiment can be achieved. When disposing thepolarizer 21 on the surface of the pupil 22 a (FIG. 6 ), it is preferable that the directions of amplitude J11 to J14 and the extending directions of the four pairs of light shielding portions match, respectively. - Further considered is a general case in which the number of directions of amplitude of polarized light passing through the
polarizer 21 is N and a minimum positive angle made by the respective directions of amplitude is (360/2N) degrees. In this case, thepolarizer 21 is equally divided into 2N regions, and polarized light passing through regions facing each other has the same direction of amplitude. That is, distributions of the directions of polarized light passing through thepolarizer 21 form a regular polygon with 2N members. - The use of
such polarizer 21 in the case where there exist N pairs of light shielding portions in the pattern on thephotomask 18, each pair extending in one direction, and the extending directions of the respective pairs cross each other at a positive minimum angle of (360/2N) degrees can achieve the same effects as in the second preferred embodiment. -
FIG. 14 schematically shows the directions of amplitude J of polarized light passing through thepolarizer 21 according to the present embodiment. Thepolarizer 21 has a ring-shaped region S0 centering at the position D. The region S0 is interposed between two circles concentric with respect to the position D. Selection of polarized light is not conducted in the range surrounded by the region S0, but incident light is transmitted. - The directions of amplitude J of polarized light are concentric with respect to the position D, similarly to the directions shown in
FIG. 8 . Thepolarizer 21 is disposed on the surface of the pupil 22 a such that the position D lies exactly on thecenter 22 b. Thepolarizer 21 may consist of the region S0 alone. - As shown in
FIG. 4 , where the angle of incidence θ is about 40 degrees or smaller, a difference in reflectivity between s-polarized light and p-polarized light increases with an increase in the angle of incidence θ. Thus, p-polarized light resulting from incident light having a great angle of incidence may be limitedly cut off. The region S0 shown inFIG. 14 is a peripheral portion with respect to the center D, where the angle of incidence is great. Therefore, the use of thepolarizer 21 according to the present embodiment can improve the contrast of illumination light made incident at such an angle that resolution characteristics significantly degrade, similarly to the first preferred embodiment. -
FIGS. 15 and 16 each schematically show the directions of amplitude of polarized light passing through another type ofpolarizer 21 according to the present embodiment.FIG. 15 shows the structure in which the regions S1 to S4 of thepolarizer 21 shown inFIG. 12 are transformed into regions S21 to S24 limited in a range at a certain distance from the center D.FIG. 16 shows the structure in which the regions S11 to S18 are transformed into regions S31 to S38 limited in a range at a certain distance from the center D. - Even where the directions of amplitude of transmitted light are limited in a ring-shaped region as in the present embodiment, the contrast of illumination light made incident at such an angle that resolution characteristics significantly degrade can be improved, similarly to the third preferred embodiment.
- While the invention has been shown and described in detail, the foregoing description is in all aspects illustrative and not restrictive. It is therefore understood that numerous modifications and variations can be devised without departing from the scope of the invention.
Claims (4)
1-17. (canceled)
18. An exposure method using an optical system employing a polarizer, wherein said polarizer include an even number of regions arranged adjacently to one another around a center and is provided on the surface of a pupil of said optical system, and directions of amplitude of light passing through said even number of regions distribute in the form of a regular polygon with an even number of members.
19. The exposure method according to claim 18 , wherein said even number of regions are arranged annularly.
20. The exposure method according to claim 18 , wherein
a light passing through said polarizer is incident on a photoresist over a wafer and expose said photoresist, and
content of s-polarized light in said light incident on said photoresist is larger than content of p-polarized light in said light.
Priority Applications (1)
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US12/359,673 US20090135481A1 (en) | 2003-07-02 | 2009-01-26 | Polarizer, projection lens system, exposure apparatus and exposing method |
Applications Claiming Priority (4)
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JP2003-190205 | 2003-07-02 | ||
JP2003190205A JP2005024890A (en) | 2003-07-02 | 2003-07-02 | Polarizer, projection lens system, aligner, and exposure method |
US10/883,007 US7499148B2 (en) | 2003-07-02 | 2004-07-02 | Polarizer, projection lens system, exposure apparatus and exposing method |
US12/359,673 US20090135481A1 (en) | 2003-07-02 | 2009-01-26 | Polarizer, projection lens system, exposure apparatus and exposing method |
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US10/883,007 Division US7499148B2 (en) | 2003-07-02 | 2004-07-02 | Polarizer, projection lens system, exposure apparatus and exposing method |
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US20090135481A1 true US20090135481A1 (en) | 2009-05-28 |
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US10/883,007 Expired - Fee Related US7499148B2 (en) | 2003-07-02 | 2004-07-02 | Polarizer, projection lens system, exposure apparatus and exposing method |
US12/359,673 Abandoned US20090135481A1 (en) | 2003-07-02 | 2009-01-26 | Polarizer, projection lens system, exposure apparatus and exposing method |
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US10/883,007 Expired - Fee Related US7499148B2 (en) | 2003-07-02 | 2004-07-02 | Polarizer, projection lens system, exposure apparatus and exposing method |
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US (2) | US7499148B2 (en) |
JP (1) | JP2005024890A (en) |
CN (1) | CN100514095C (en) |
Families Citing this family (12)
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KR20150036786A (en) | 2003-04-09 | 2015-04-07 | 가부시키가이샤 니콘 | Exposure method and apparatus, and device manufacturing method |
TWI474132B (en) | 2003-10-28 | 2015-02-21 | 尼康股份有限公司 | Optical illumination device, projection exposure device, exposure method and device manufacturing method |
JP2005136244A (en) * | 2003-10-31 | 2005-05-26 | Semiconductor Leading Edge Technologies Inc | Exposure method |
TWI612338B (en) | 2003-11-20 | 2018-01-21 | 尼康股份有限公司 | Optical illuminating apparatus, exposure device, exposure method, and device manufacturing method |
US8270077B2 (en) * | 2004-01-16 | 2012-09-18 | Carl Zeiss Smt Gmbh | Polarization-modulating optical element |
KR101233879B1 (en) * | 2004-01-16 | 2013-02-15 | 칼 짜이스 에스엠티 게엠베하 | Polarization-modulating optical element |
US20070019179A1 (en) * | 2004-01-16 | 2007-01-25 | Damian Fiolka | Polarization-modulating optical element |
TWI505329B (en) | 2004-02-06 | 2015-10-21 | 尼康股份有限公司 | Optical illumination apparatus, light-exposure apparatus, light-exposure method and device manufacturing method |
US7324280B2 (en) | 2004-05-25 | 2008-01-29 | Asml Holding N.V. | Apparatus for providing a pattern of polarization |
JP5267029B2 (en) | 2007-10-12 | 2013-08-21 | 株式会社ニコン | Illumination optical apparatus, exposure apparatus, and device manufacturing method |
US20140240705A1 (en) * | 2013-02-27 | 2014-08-28 | Kabushiki Kaisha Toshiba | Semiconductor device, reticle method for checking position misalignment and method for manufacturing position misalignment checking mark |
CN104656265A (en) * | 2013-11-25 | 2015-05-27 | 曲阜师范大学 | Polarization plane rotary light intensity spatial distribution regulator |
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US4286843A (en) * | 1979-05-14 | 1981-09-01 | Reytblatt Zinovy V | Polariscope and filter therefor |
US5365371A (en) * | 1992-02-10 | 1994-11-15 | Mitsubishi Denki Kabushiki Kaisha | Projection exposure apparatus |
US6333780B1 (en) * | 1999-12-27 | 2001-12-25 | Mitsubishi Denki Kabushiki Kaisha | Projection aligner |
US20020176166A1 (en) * | 2001-05-22 | 2002-11-28 | Carl Zeiss Semiconductor Manufacturing Technologies Ag | Polarizer and microlithography projection system with a polarizer |
US20040119954A1 (en) * | 2002-12-10 | 2004-06-24 | Miyoko Kawashima | Exposure apparatus and method |
Family Cites Families (1)
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US5438761A (en) * | 1993-09-16 | 1995-08-08 | Krumszyn; Luba M. | Rotatable carpenter's level |
-
2003
- 2003-07-02 JP JP2003190205A patent/JP2005024890A/en active Pending
-
2004
- 2004-07-02 US US10/883,007 patent/US7499148B2/en not_active Expired - Fee Related
- 2004-07-02 CN CNB2004100628746A patent/CN100514095C/en not_active Expired - Fee Related
-
2009
- 2009-01-26 US US12/359,673 patent/US20090135481A1/en not_active Abandoned
Patent Citations (6)
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US4286843A (en) * | 1979-05-14 | 1981-09-01 | Reytblatt Zinovy V | Polariscope and filter therefor |
US5365371A (en) * | 1992-02-10 | 1994-11-15 | Mitsubishi Denki Kabushiki Kaisha | Projection exposure apparatus |
US5436761A (en) * | 1992-02-10 | 1995-07-25 | Mitsubishi Denki Kabushiki Kaisha | Projection exposure apparatus and polarizer |
US6333780B1 (en) * | 1999-12-27 | 2001-12-25 | Mitsubishi Denki Kabushiki Kaisha | Projection aligner |
US20020176166A1 (en) * | 2001-05-22 | 2002-11-28 | Carl Zeiss Semiconductor Manufacturing Technologies Ag | Polarizer and microlithography projection system with a polarizer |
US20040119954A1 (en) * | 2002-12-10 | 2004-06-24 | Miyoko Kawashima | Exposure apparatus and method |
Also Published As
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US7499148B2 (en) | 2009-03-03 |
JP2005024890A (en) | 2005-01-27 |
CN100514095C (en) | 2009-07-15 |
US20050041232A1 (en) | 2005-02-24 |
CN1576908A (en) | 2005-02-09 |
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