JP2007019564A - Illumination optical system, aligner and manufacturing method of device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illumination optical system enabling to obtain a desired effective light source depending on the pattern change and to relatively displace each partial effective light source. <P>SOLUTION: An illumination optical system is provided for illuminating a surface to be illuminated using a light flux from a light source, including illumination light generating means for generating light quantity distribution in a plane having a relationship of Fourier transformation with respect to the surface to be illuminated. The illumination light generating means includes a prism having incident planes of the light flux that are first polygonal pyramidal planes, and exit planes of the light flux that are second polygonal pyramid planes, and a flat top. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates generally to illumination optical systems, and more particularly to illumination optical systems used to manufacture devices such as single crystal substrates for semiconductor wafers and glass substrates for liquid crystal displays (LCDs). The present invention is suitable, for example, for an illumination optical system that projects and exposes a contact hole array pattern or a mixture of isolated contact holes and contact hole arrays on an object to be processed in a photolithography process.

  Due to the recent demand for smaller and thinner electronic devices, there is an increasing demand for miniaturization of semiconductor elements mounted on electronic devices. For example, according to the design rule, it is expected that circuit pattern formation of 100 nm or less will be achieved in a mass production process, and that it will be further shifted to circuit pattern formation of 80 nm or less in the future. The main processing technique is photolithography, and a mask pattern drawn on a mask or a reticle (in this specification, these terms are used interchangeably) is projected onto a wafer by a projection optical system to transfer the pattern. Projection exposure apparatuses are conventionally used.

  The resolution R of the projection exposure apparatus is given by the following Rayleigh equation using the wavelength λ of the light source and the numerical aperture (NA) of the projection optical system.

  On the other hand, the focal range in which constant imaging performance can be maintained is called the focal depth, and the focal depth DOF is given by the following equation.

Note that when the depth of focus DOF is small, focusing becomes difficult, and it is required to increase the flatness (flatness) and focus accuracy of the substrate.

  The mask pattern includes adjacent periodic line and space (L & S) patterns, adjacent and periodic (that is, arranged at intervals of the same level as the hole diameter), isolated isolated contact holes without proximity, Including other isolated patterns, etc., in order to transfer a pattern with high resolution, it is necessary to select an optimal illumination condition according to the type of pattern.

  In recent years, the semiconductor industry is shifting to a system chip having a higher value-added and a variety of patterns, and it has become necessary to mix a plurality of types of contact patterns in the mask. However, contact hole patterns in which contact hole arrays and isolated contact holes are mixed cannot be exposed simultaneously with high resolution.

  Therefore, various methods for increasing the resolution limit and increasing the depth of focus are proposed only for contact hole rows and vertical and horizontal repetitive wiring patterns. As such a method, for example, there are a double exposure (or multiple exposure) method in which different types of patterns are separately exposed using two masks, and a method in which one mask described later is exposed under special illumination conditions. is there. In addition, there is a method for enhancing the resolution of the regular pattern by providing various auxiliary patterns to the mask pattern.

  However, a function of the illumination optical system that is commonly required for the above-described method is that the illumination condition (specifically, the effective light source distribution of the illumination optical system) when the size and arrangement of the mask pattern changes from process to process. ) Cannot be freely changed, and there is a problem in that exposure cannot be performed under optimum illumination conditions and high resolution cannot be obtained.

  In the prior art, a conversion function from a normal circular effective light source to an annular effective light source or a switching mechanism to a quadrupole effective light source has been disclosed. However, in order to cope with future pattern miniaturization, it is necessary to improve resolution performance by changing the effective light source of the same type.

  An illumination optical system according to a first aspect of the present invention is an illumination optical system that illuminates a surface to be illuminated with a light beam from a light source, and a light amount on a surface that has a Fourier transform relationship with respect to the surface to be illuminated. Illumination light generation means for generating a distribution, the illumination light generation means includes a prism whose incident surface of the light beam is a first polygonal pyramid surface and whose emission surface of the light beam is a second polygonal pyramid surface; The apex of the prism is flattened.

  Further objects and other features of the present invention will become apparent from the preferred embodiments described below with reference to the accompanying drawings.

  According to the illumination optical system of the present invention, a desired effective light source can be obtained in accordance with changes in dimensions and arrangement of the mask pattern for each process.

  Hereinafter, an exposure apparatus which is an exemplary embodiment of the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to these examples, and each constituent element may be alternatively substituted as long as the object of the present invention is achieved. In addition, in each figure, the same reference number is attached | subjected about the same member and the overlapping description is abbreviate | omitted.

  FIG. 1 is a schematic block diagram showing an exemplary embodiment of an exposure apparatus 100 as one aspect of the present invention. The exposure apparatus 100 includes an illumination device 200, a mask 300, a projection optical system 400, and a plate 500, as well shown in FIG.

  The exposure apparatus 100 is a projection exposure apparatus that exposes a circuit pattern formed on the mask 300 to the plate 500 by, for example, a step-and-repeat method or a step-and-scan method. Such an exposure apparatus is suitable for a lithography process of submicron or quarter micron or less, and in the present embodiment, a step-and-scan exposure apparatus (also referred to as a “scanner”) will be described as an example. Here, in the “step and scan method”, the wafer is continuously scanned with respect to the mask to expose the mask pattern onto the wafer, and after the exposure of one shot is completed, the wafer is stepped to the next shot. The exposure method moves to the exposure area. The “step and repeat method” is an exposure method in which the wafer is stepped for each batch exposure of shots of the wafer and the next shot is moved to the exposure region.

  The illumination device 200 illuminates a mask 300 on which a transfer circuit pattern is formed, and includes a light source unit 210 and an illumination optical system 220.

The light source unit 210 uses, for example, a laser as a light source. As the laser, an ArF excimer laser with a wavelength of about 193 nm, a KrF excimer laser with a wavelength of about 248 nm, an F ₂ laser with a wavelength of about 157 nm can be used, but the type of laser is not limited to an excimer laser, and the number of lasers Is not limited. The light source that can be used for the light source unit 210 is not limited to a laser, and one or a plurality of lamps such as a mercury lamp can also be used.

  The illumination optical system 220 is an optical system that illuminates an irradiated surface (for example, the mask 300) having a desired pattern using the light beam emitted from the light source unit 210. In this embodiment, the light beam shaping optical system 221; A condensing optical system 222, an optical pipe (light beam mixing means) 223, a condensing zoom lens 224, a fly-eye lens 225, a diaphragm member 226, an irradiation lens 227, a field diaphragm 228, and an imaging lens 229a 229b, a deflection mirror 230, and an illumination light generation means 240.

  The light beam emitted from the light source unit 210 is converted into a desired light beam shape by the light beam shaping optical system 221, and is collected near the incident surface 223 a of the optical pipe 223 by the condensing optical system 222. The condensing optical system 222 is replaced with a condensing optical system 222a having a different exit angle in order to make the angle of the light beam incident on the fly-eye lens 225 appropriate even if the subsequent condensing zoom lens 224 is zoomed. It has a possible configuration.

  In the case where the optical pipe 223 is formed of a glass rod, the condensing point P by the condensing optical system 222 (or 222a) is from the incident surface 223a of the optical pipe 223 in order to increase the durability of the glass rod. Defocused to the light source unit 210 side.

  The condensing zoom lens 224 condenses the light beam from the optical pipe 223 on the incident surface 225 a of the fly-eye lens (multi-beam generating means) 225.

  The condensing zoom lens 224 forms an image of the exit surface 223b of the optical pipe 223 on the entrance surface 225a of the fly-eye lens 225 at a predetermined magnification, and both are substantially conjugated. In addition, by using the condenser zoom lens 224 as a zoom lens having a variable magnification, it is possible to adjust a light flux region incident on the fly-eye lens 225, and a plurality of illumination conditions can be formed.

  In the vicinity of the exit surface 225b of the fly-eye lens 225 is a secondary light source (effective light source), and an aperture member 226 is disposed there in order to block unnecessary light and form a desired effective light source. The aperture member 226 has a variable aperture size and shape by an aperture drive mechanism (not shown).

  The irradiation lens 227 superimposes a secondary light source formed near the exit surface 225 b of the fly-eye lens 225 on the field stop 228. The field stop 228 is composed of a plurality of movable light-shielding plates, and defines an illumination area on the mask 300 surface, which is an irradiated surface, so that an arbitrary opening shape is formed.

  The imaging lenses 229a and 229b transfer the aperture shape of the field stop 228 via the deflection mirror 230 onto the mask 300 that is the irradiated surface.

  The illumination light generation means 240 includes an element for converting the light flux from the optical pipe 223 into an annular shape or a quadrupole shape according to illumination conditions (annular illumination, quadrupole illumination, etc.).

  Here, the illumination light generation means 240 will be described in detail. As shown in FIG. 2, in the case of forming an effective light source distribution having an annular light emitting portion A that has been well known from the past, the illumination light generating means 240 has an incident side (that is, as shown in FIG. The prism 250 is provided with a concave conical surface (or flat surface) 250a on the incident surface and a convex conical surface 250b on the exit side (that is, the exit surface). FIG. 2 is a schematic diagram showing an annular effective light source distribution, and FIG. 3 is a schematic diagram showing a prism 250 for forming the effective light source distribution shown in FIG.

Further, as shown in FIG. 4, in order to form a quadrupole effective light source distribution having the quadrupole light emitting part B, the illumination light generating means 240 is provided on the incident side (ie, incident side as shown in FIG. 5). A prism 260 having a concave quadrangular pyramid surface (or flat surface) 260a on the surface and a convex quadrangular pyramid surface 260b on the exit side (that is, the exit surface) may be used. At this time, the angles θ ₁ and θ ₂ formed by the ridgelines 260c and 260d of the quadrangular pyramids on the entrance surface and the exit surface and the optical axis may be equal, and the illumination efficiency is improved or the region emits light in a quadrupole shape (see FIG. In order to change the portion B) of FIG. 4, the angle θ ₁ on the incident side may be different from the angle θ ₂ on the exit side. The same applies to the conical prism 250 shown in FIG. 4 is a schematic diagram showing a quadrupole-shaped effective light source distribution, and FIG. 5 is a schematic diagram showing a prism 260 for forming the effective light source distribution shown in FIG. It is also possible to form a pentapole effective light source distribution having a partial effective light source in the middle of the four partial effective light sources by flattening the apex of the prism 260 by a predetermined amount.

  In order to form an effective light source distribution having the first illumination area C and the second illumination area D as shown in FIG. 6, the illumination light generation means 240 is arranged on the incident side (ie, as shown in FIG. The prism 270 is provided with a concave quadrangular pyramid surface 270a on the incident surface and a convex conical surface 270b on the exit side (that is, the exit surface). In this way, by combining the polyhedron that has the function of splitting the luminous flux and the conical surface that appropriately superimposes the split luminous flux, the effective light source distribution as shown in FIG. Formation is possible.

  When a predetermined mask having a desired pattern and an auxiliary pattern is illuminated by an illumination optical system that forms an effective light source distribution having the first illumination area C and the second illumination area D, contact hole rows and vertical and horizontal directions are obtained. It is possible to increase the resolution limit of the repeated wiring pattern and increase the depth of focus. The details will be described below.

As the mask 300 in FIG. 1, a mask in which a desired contact hole pattern such as the mask 300a shown in FIG. 15 is arranged at a predetermined period and an auxiliary pattern (dummy contact hole pattern) is arranged around the mask 300a is used. Here, FIG. 15 is a schematic view of a binary mask in which a desired contact hole pattern and auxiliary pattern are formed. The mask shown in FIG. 15 includes a desired contact hole pattern 31 and auxiliary pattern 32 that are translucent portions, and a light shielding portion 33. In addition, the phase of each light transmission part is equal. When the hole diameter is P, the contact hole pattern 31 and the auxiliary pattern 32 are aligned with a pitch P ₀ = 2P in the vertical and horizontal directions to form a contact hole row two-dimensionally.

  With respect to this mask 300a, cross oblique incidence illumination for resolving contact holes and false resolution caused by the cross oblique incidence illumination are suppressed (that is, the exposure amount corresponding to the false resolution pattern is suppressed (exposure). The desired contact hole pattern can be exposed to the plate 500 with high resolving power by performing illumination that emphasizes the exposure amount of the desired contact hole pattern (high increase in exposure amount). The details will be described below.

  When the contact hole pitch is small, when σ illumination is performed using the mask 300a of FIG. 15, the diffracted light on the pupil plane of the projection optical system 400 deviates from the pupil except for the 0th-order diffracted light. End up. As shown in FIG. 16, 0th-order diffracted light 10 is generated, and diffracted light of other diffraction orders becomes diffracted light 11 to 18 on the pupil plane. Therefore, diffracted light other than the 0th order goes out of the pupil of the projection lens, and no pattern is formed under such conditions. Here, FIG. 16 shows the position of the diffracted light on the pupil plane of the projection optical system 400 when the mask 300a shown in FIG. 15 is illuminated with a small σ, and the position where the diffracted light moves when the oblique illumination is performed. It is a schematic diagram.

  Therefore, it is necessary to perform illumination so that these diffracted lights 11 to 18 enter the pupil. For example, taking the two diffracted lights 10 and 15 as an example, in order to make such diffracted lights come to the oblique line region of the pupil plane of the projection optical system 400 shown in FIG. 16, the effective light source surface shown in FIG. The oblique incident illumination is set as indicated by the rectangular area a. The diffracted light indicated by 10 ′ and 15 ′ moves to rectangular areas b 1 and b 2 indicated by crosses and diagonal lines, respectively, and enters both ends of the pupil of the projection optical system 400. Two diffracted lights are incident on the pupil by an effective light source indicated by one rectangle, and a linear interference fringe having an equal pitch is formed on the plate 500 by interference between the two. Similarly, in the two diffracted lights 10 and 17, the oblique incidence illumination described in 10 and 15 can be set. By combining four such rectangular effective light source regions as shown in FIG. 18, vertical and horizontal equal-pitch linear interference fringes are formed on the plate 500, and the intensity is high at the intersection where the light intensities overlap. A part and a small part appear two-dimensionally periodically. As shown in FIG. 19A, the effective light source shape at this time is four rectangles having a length in the direction orthogonal to the radial direction of the pupil arranged in the cross.

  In the mask 300a shown in FIG. 15, since the hole diameter of the desired contact hole pattern is larger than that of the auxiliary pattern, only the portion is stronger than the periphery, and the desired contact hole pattern is formed on the plate 500. Will be. However, if the cross-shaped oblique incidence illumination is simply applied, a false resolution pattern is generated on the plate 500 as shown in FIGS. 20 (a) and 20 (b). A necessary pattern is born (FIG. 20 is a diagram showing a simulation of a resolution pattern on the plate 500 corresponding to the aperture shape of the right aperture stop).

That is, in terms of the exposure amount, it looks like a wavy line drawn with a thin solid line shown in FIG. 21, and at the desired diameter exposure amount level (resist threshold), the pseudo-resolution pattern P ₂ between the desired patterns P _1. (Here, FIG. 21 is a diagram showing the exposure amount in the oblique incidence illumination and the modified illumination of the present invention and an image on the plate 500 corresponding to the exposure amount).

  Therefore, as shown in FIG. 16, an effective light source distribution in which only at least one diffracted light is incident on the pupil surface is added except for a region c represented by linearly connecting two diffracted light positions on the pupil surface. In this case, it is convenient to use zero-order light as one diffracted light because the oblique incident angle can be reduced. FIG. 22 shows an example of the effective light source distribution. In order to perform such illumination, for example, the illumination may be set so that one diffracted light 10 'is shown as a dark sector area a on the pupil plane. As a result, the diffracted light indicated by 10 ′ moves to the region b indicated as a bright fan shape, and the diffracted light enters the pupil plane 320. There are a total of four corresponding to such conditions, and eventually an effective light source having a shape as shown in FIG.

  As described above, the illumination system has an effective light source distribution in which two diffracted lights enter the pupil (see FIG. 19A) and an effective light source distribution in which one diffracted light enters the pupil (see FIG. 19B). As shown in FIG. 19C, modified illumination having an effective light source with the center removed in a cross shape can be performed. It is understood that by performing the modified illumination having such an effective light source distribution, the false resolution disappears and only a desired pattern can be obtained on the surface of the plate 500 as shown in FIG.

That is, the exposure amount on the plate 500 is like a wavy line drawn with a thick solid line shown in FIG. 21, and only the exposure amount corresponding to the desired pattern of the mask at the desired diameter exposure amount level (resist threshold). There are increased, it is possible to obtain only the desired pattern P ₃ of spurious resolution pattern has disappeared.

  From the above, it can be seen that the resolution of the contact hole pattern is improved by performing modified illumination having an effective light source distribution as shown in FIG. 19C on the mask 300a of FIG.

  Further, in the effective light source distribution of FIG. 19C, the portion for performing illumination for resolving the contact hole corresponds to the first illumination region D, and the false resolution caused by the illumination is suppressed ( It can also be seen that the portion for performing illumination (which improves the contrast between the desired contact hole pattern and the auxiliary pattern) corresponds to the second illumination area C (see FIG. 6).

  The effective light source distribution shown in FIG. 6 can also be formed by forming the concave quadrangular pyramid surface 260a and the convex quadrangular pyramid surface 260b of the prism 260 shown in FIG. Here, FIG. 6 is a schematic diagram showing an effective light source distribution having an octapole shape proposed in the present invention, and FIG. 7 is a schematic diagram showing a prism 270 for forming the effective light source distribution shown in FIG.

  If the prism 270 is used for the illumination light generation means 240, it is not necessary to cut out light more than necessary by the diaphragm member 226 disposed in the vicinity of the fly-eye lens exit surface 225b, and an effective light source distribution can be formed with high illumination efficiency. There is an effect that.

  Further, the illumination light generation means 240 is constituted by a pair of prisms 280 (a prism 282 having a polyhedron 282a and a prism 284 having a conical surface 284a) as shown in FIGS. 8 and 9, and can be relatively moved in the optical axis direction. If so, it is possible to form a wider variety of effective light source distributions. 8 and 9 are schematic views showing a pair of prisms 280 for forming the effective light source distribution shown in FIG. 6. FIG. 8 shows a case where the distance L between the pair of prisms 280 is small, and FIG. The case where the space | interval L of a pair of prisms 280 is large is shown.

  Referring to FIG. 8, when the distance L between the pair of prisms 280 is small, as shown in FIG. 10, the length C1 of the first illumination region C is large and the width D1 of the second illumination region D is small. A light source distribution is formed. FIG. 10 is a schematic diagram showing the relationship between the prism spacing L of the pair of prisms 280 shown in FIG. 8 and the effective light source shape formed.

  On the other hand, referring to FIG. 9, when the distance L between the pair of prisms 280 is large, the length C1 of the first illumination region C is small and the width D1 of the second illumination region D is shown in FIG. A large effective light source distribution is formed. FIG. 11 is a schematic diagram showing the relationship between the prism spacing L of the pair of prisms 280 shown in FIG. 9 and the effective light source shape formed.

  Therefore, the relative ratio (light quantity ratio or area ratio) between the first illumination area C and the second illumination area D can be adjusted so that the assist effect by the auxiliary pattern is optimized according to the pattern to be formed. It becomes possible.

  Further, when combined with the condenser zoom lens 224 in the subsequent stage, the size (σ value) of the effective light source distribution can be adjusted while maintaining the relative ratio between the first illumination area C and the second illumination area D. It becomes possible.

  8 and 9, the incident side of the prism 282 on the light source unit 210 side is a concave polyhedron, the exit side is a plane, the entrance surface of the prism 284 on the mask 300 side is a plane, and the exit side is a convex cone. Of course, the incident surface of the prism 282 on the light source unit 210 side may be a plane, the exit side may be a concave polyhedron, the incident surface of the prism 284 on the mask 300 side may be a convex cone, and the exit side may be a plane. Furthermore, it is also possible to arrange the conical and polyhedral surfaces in reverse. However, when making different shapes approach as a pair of prisms, the configuration shown in FIGS. 8 and 9 is preferable.

  In the above, a combination of a cone and a polyhedron has been described as a pair of prisms having differently shaped surfaces, but a combination of a polyhedron and a polyhedron (for example, a quadrangular pyramid surface and a quadrangular pyramid surface) may be used. Needless to say.

In addition, the effective light source distribution may be made variable by making at least one of the prism on the light source unit 210 side and the prism of the mask 300 rotatable with respect to the optical axis (for example, when both have quadrangular pyramid surfaces). Switching between the quadrupole illumination as shown in FIG. 4 and the octupole illumination as shown in FIG. 6 is possible)
Furthermore, in the above, by making some of the plurality of prisms movable in the optical axis direction, various effective light source distributions can be formed. However, as in the prisms 250, 260, and 270 described above, they are different from each other. Various effective light source distributions can also be formed by switching prisms having properties on the turret.

  Next, with reference to FIG. 12, an illumination light generation unit 290 that is a modification of the illumination light generation unit 240 will be described. FIG. 12 is a schematic block diagram showing a projection exposure apparatus 100A including an illumination light generation means 290 that is a modification of the illumination light generation means 240. Compared with the illumination light generation means 240 shown in FIG. 1, the illumination light generation means 290 is substantially in a Fourier transform relationship with the fly-eye lens entrance surface 225a (in this specification, the Fourier transform relationship is optically the pupil). A diffractive optical element 295 (for example, BO (Baily Optics) or CGH (Computer Generated Hologram)) is located at a position that becomes a plane and an object plane (or image plane), or a relationship between an object plane (or image plane) and a pupil plane. Etc.) is different.

  The diffractive optical element 295 is designed so as to form a desired distribution, that is, an effective light source distribution on a plane having a Fourier transform relationship when parallel light is incident. Therefore, if the effective light source distribution shown in FIG. 6 is to be formed, a corresponding diffractive optical element may be designed and manufactured. As for the design and production of the diffractive optical element 295, methods described in Japanese Patent Application Laid-Open No. 11-054426 and an introduction to the diffractive optical element (supervision: Japan Society of Applied Physics, published by Optonics) can be used Detailed description here is omitted.

  Further, if the incident light to the diffractive optical element 295 is not parallel and has an angle, an image formed on the Fourier transform plane is blurred, so that the NA defined by the condensing optical system 222 is variable. With the optical optical system 222a, the widths of the first illumination area C and the second illumination area D shown in FIG. 6 can be made variable. The condensing optical system 222a may be configured to switch an optical system that emits different NAs using a turret, or may be a zoom system with variable NA.

  As the illumination light generation means 290, a plurality of optical elements 295a that can be exchanged using a turret-like switching means or the like according to a desired pattern formed on the mask 300 may be used.

  In the above embodiment, the illumination light beam forming means 240 and 290 are arranged between the optical pipe 223 and the fly-eye lens 225. However, a second fly-eye lens is used in place of the optical pipe 223. In this case, the illumination light beam forming means 240, 290 may be disposed between the second fly-eye lens and the fly-eye lens 225. At that time, it is desirable that the illumination light beam forming means 240 and 290 be disposed at a position optically Fourier-transformed with respect to the incident surface of the fly-eye lens 225.

  Returning to FIG. 1 again, the mask 300 is made of, for example, quartz, on which a circuit pattern (or image) to be transferred is formed, and supported and driven by a mask stage (not shown). The diffracted light emitted from the mask 300 passes through the projection optical system 400 and is projected onto the plate 500. The mask 300 and the plate 500 are arranged in a conjugate relationship. Since the exposure apparatus 100 is a step-and-scan exposure apparatus, the mask pattern is reduced and projected onto the plate 500 by scanning the mask 300 and the plate 500.

  The projection optical system 400 forms an image of a light beam from an object plane (for example, the mask 300) on an image plane (for example, an object to be processed such as the plate 500). The projection optical system 400 includes an optical system including only a plurality of lens elements, an optical system (catadioptric optical system) having a plurality of lens elements and at least one concave mirror, a plurality of lens elements, and at least one kinoform. An optical system having a diffractive optical element such as an all-mirror optical system can be used. When correction of chromatic aberration is necessary, a plurality of lens elements made of glass materials having different dispersion values (Abbe values) can be used, or the diffractive optical element can be configured to generate dispersion in the opposite direction to the lens element. To do.

  The plate 500 is a wafer in this embodiment, but widely includes a liquid crystal substrate and other objects to be processed (objects to be exposed). Photoresist is applied to the plate 500. The photoresist coating process includes a pretreatment, an adhesion improver coating process, a photoresist coating process, and a prebaking process. Pretreatment includes washing, drying and the like. The adhesion improver coating process is a surface modification process for improving the adhesion between the photoresist and the base (that is, a hydrophobic process by application of a surfactant), and an organic film such as HMDS (Hexmethyl-disilazane) is used. Coat or steam. Pre-baking is a baking (baking) step, but is softer than that after development, and removes the solvent.

  The plate 500 is supported by a plate stage (not shown). Since any configuration known in the art can be applied to the plate stage, a detailed description of the structure and operation is omitted here. For example, the plate stage can move the plate 500 in the XY directions using a linear motor. The mask 300 and the plate 500 are synchronously scanned, for example, and the positions of a plate stage and a mask stage (not shown) are monitored by, for example, a laser interferometer, and both are driven at a constant speed ratio. The plate stage is provided on a stage surface plate supported on a floor or the like via a damper, for example, and the mask stage and the projection optical system 400 are, for example, a base mounted on the floor or the like. It is provided on a lens barrel surface plate (not shown) supported on a frame via a damper or the like.

  In the exposure, the light beam emitted from the light source unit 210 illuminates the mask 300 by the illumination optical system 220. Light that passes through the mask 300 and reflects the mask pattern is imaged on the plate 500 by the projection optical system 400.

  The illumination optical system 200 used by the exposure apparatus 100 can illuminate the mask 300 under optimum illumination conditions in accordance with a desired pattern formed on the mask 300, so that the device (semiconductor) with high resolution and throughput can be economically obtained. Elements, LCD elements, imaging elements (CCD, etc.), thin film magnetic heads, etc.) can be provided.

  Next, an embodiment of a device manufacturing method using the above-described exposure apparatus 100 will be described with reference to FIGS. FIG. 12 is a flowchart for explaining how to fabricate devices (ie, semiconductor chips such as IC and LSI, LCDs, CCDs, and the like). Here, the manufacture of a semiconductor chip will be described as an example. In step 1 (circuit design), a device circuit is designed. In step 2 (mask production), a mask on which the designed circuit pattern is formed is produced. In step 3 (wafer manufacture), a wafer is manufactured using a material such as silicon. Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by lithography using the mask and the wafer. Step 5 (assembly) is called a post-process, and is a process for forming a semiconductor chip using the wafer created in step 4, and includes processes such as an assembly process (dicing and bonding) and a packaging process (chip encapsulation). . In step 6 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device created in step 5 are performed. Through these steps, the semiconductor device is completed and shipped (step 7).

  FIG. 13 is a detailed flowchart of the wafer process in Step 4. In step 11 (oxidation), the surface of the wafer is oxidized. In step 12 (CVD), an insulating film is formed on the surface of the wafer. In step 13 (electrode formation), an electrode is formed on the wafer by vapor deposition or the like. Step 14 (ion implantation) implants ions into the wafer. In step 15 (resist process), a photosensitive agent is applied to the wafer. Step 16 (exposure) uses the exposure apparatus 100 to expose a circuit pattern on the mask onto the wafer. In step 17 (development), the exposed wafer is developed. In step 18 (etching), portions other than the developed resist image are removed. In step 19 (resist stripping), the resist that has become unnecessary after the etching is removed. By repeatedly performing these steps, multiple circuit patterns are formed on the wafer. According to the device manufacturing method of the present embodiment, it is possible to manufacture a higher quality device than before.

  Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist thereof.

1 is a schematic block diagram showing an exemplary embodiment of an exposure apparatus as one aspect of the present invention. It is the schematic which shows ring-shaped effective light source distribution. It is the schematic which shows the prism for forming the effective light source distribution shown in FIG. It is the schematic which shows the effective light source distribution of quadrupole shape. It is the schematic which shows the prism for forming the effective light source distribution shown in FIG. It is the schematic which shows the effective light source distribution of the octupole shape proposed by this invention. It is the schematic which shows the prism for forming the effective light source distribution shown in FIG. It is the schematic which shows an example of a pair of prism for forming the effective light source distribution shown in FIG. It is the schematic which shows an example of a pair of prism for forming the effective light source distribution shown in FIG. It is the schematic which shows the relationship between the prism space | interval L of a pair of prism 280 shown in FIG. 8, and the effective light source shape formed. It is the schematic which shows the relationship between the prism space | interval L of a pair of prism shown in FIG. 9, and the effective light source shape formed. 1 is a schematic block diagram showing an exemplary embodiment of an exposure apparatus as one aspect of the present invention. It is a flowchart for demonstrating manufacture of devices (semiconductor chips, such as IC and LSI, LCD, CCD, etc.). 14 is a detailed flowchart of the wafer process in Step 4 shown in FIG. 13. It is a figure which shows the outline of a binary mask. It is the schematic diagram which showed the position of the diffracted light on a pupil surface when small σ illumination is carried out to the binary mask shown in FIG. 15, and the position to which a diffracted light moves when carrying out oblique incidence illumination. It is a schematic diagram for demonstrating effective light source distribution. It is a schematic diagram for demonstrating effective light source distribution. It is a schematic diagram for demonstrating effective light source distribution. It is the figure which showed the simulation of the resolution pattern on a pattern surface. It is the figure which showed the image on the pattern corresponding to the exposure amount in modified illumination, and the said exposure amount. It is a figure which shows an example of effective light source distribution.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Exposure apparatus 200 Illumination device 210 Light source part 220 Illumination optical system 240 Illumination light production | generation means 270 Prism 280 A pair of prism 300 Mask 400 Projection optical system 500 Plate

Claims (4)

An illumination optical system that illuminates a surface to be illuminated with a light beam from a light source,
Illumination light generating means for generating a light amount distribution on a surface that is in a Fourier transform relationship with respect to the surface to be illuminated;
The illumination light generating means includes a prism in which an incident surface of the light beam is a first polygonal pyramid surface, and an emission surface of the light beam is a second polygonal pyramid surface,
An illumination optical system characterized in that the apex of the prism is flattened.   The illumination optical system according to claim 1, wherein the illumination light generation unit generates a quintuple effective light source distribution having a partial effective light source in the middle of four partial effective light sources. The illumination optical system according to claim 1 or 2, which illuminates a reticle on the illuminated surface;
An exposure apparatus comprising: a projection optical system that projects the reticle pattern onto an object to be processed. Exposing the object to be processed using the exposure apparatus according to claim 3;
And a step of developing the exposed object to be processed.