TWI395069B - Projection optical system, exposure device and exposure method - Google Patents

Description

Projection optical system, exposure device, and exposure method

The present invention relates to a projection optical system, an exposure apparatus, and an exposure method, particularly a high resolution projection optical system to which an exposure apparatus used in a lithography process, such as a semiconductor element or a liquid crystal display element, is used.

In a lithography process for manufacturing a semiconductor element or the like, an image of a photomask is exposed on a wafer (or a glass plate) coated with a photoresist by a projection optical system using an exposure device. Then, as the degree of integration of the semiconductor element or the like increases upward, the resolution required for the projection optical system of the exposure apparatus also gradually increases.

Therefore, in order to satisfy the requirement for the resolution of the projection optical system, it is necessary to shorten the wavelength λ of the illumination light (light for exposure) and to increase the number NA of the image side openings of the projection optical system. Specifically, the resolution of the projection optical system is k. λ/NA (k is the program coefficient) is expressed. Further, when the refractive index of the medium (usually a gas such as air) between the projection optical system and the photosensitive substrate (wafer or the like) is n and the maximum incident angle toward the photosensitive substrate is θ, the number of image side openings is NA is n. Sin θ is expressed.

In the above case, when the maximum incident angle θ is increased to increase the number of image side openings, the incident angle toward the photosensitive substrate and the exit angle from the projection optical system become large. The reflection loss caused by the surface is increased, so that it is not possible to ensure a large and effective number of image side openings. However, a technique of filling a medium such as a liquid having a high refractive index in the optical path between the projection optical system and the photosensitive substrate to increase the number of apertures on the image side is known.

Generally, the refractive index fluctuation of the liquid caused by the temperature change is larger than the refractive index fluctuation of the gas such as air. Therefore, the influence of the refractive index fluctuation of the liquid caused by the temperature change is substantially unacceptable to us, and when the variation of the aberration of the projection optical system during exposure is suppressed to be small, the thickness of the liquid layer cannot be set. The larger the moving distance of the image side of the projection optical system (the distance between the optical surface of the most image side and the image plane), the larger the larger.

On the one hand, the incident light energy is arranged on the most image side in the projection optical system and becomes larger at the boundary lens adjacent to the liquid. As a result, if the boundary lens disposed at a position where the light energy is large is formed of quartz, it is easy to cause a local refractive index change (i.e., compaction) formed by volume contraction. Due to the influence of such tightening, the imaging performance of the projection optical system may be lowered.

Therefore, in order to avoid the deterioration of the imaging performance caused by the contraction in the projection optical system, even a fluorescent material having a sufficiently large transmittance is used for the light in the extreme ultraviolet region, in particular, a fluorescent material developed using a material having excellent homogeneity. Stone to form the boundary lens. Therefore, in the case where the fluoride has a property of being dissolved in water, for example, if fluorite is used to form a boundary lens and pure water is used as the immersion liquid, the optical surface of the boundary lens is easily subjected to pure water (dip The influence of the liquid is impaired, so that the imaging performance of the projection optical system cannot be maintained in a good condition for a long period of time.

In view of the problems caused by the above problems, it is an object of the present invention to provide a projection optical system which can ensure a large and effective number of image side openings when liquid is present in the optical path between image planes, and is substantially unaffected by The effect of tightening is not affected by the damage caused by the immersion liquid and can maintain good imaging performance for a long time.

Further, the present invention provides an exposure apparatus and an exposure method using the above-described projection optical system, which can ensure a large and effective image side opening number and can maintain good imaging performance for a long period of time, and the exposure apparatus and the exposure method can be The projection exposure of the high resolution is continuously performed for a long period of time.

In order to achieve the above object, a first embodiment of the present invention provides a projection optical system for forming an image of a first surface on a second surface, wherein a refractive index of air in an optical path of the projection optical system becomes 1 When the optical path between the projection optical system and the second surface is filled with a liquid having a refractive index larger than 1.1, the most second surface side of the projection optical system is formed by the first optical material and is associated with the liquid. In the bonded optical member including the first optical member and the second optical member formed by the second optical material, the thickness of the first optical member is TA, and the maximum image height in the second surface is In the case of IH, the condition of 0.1 < TA / IH < 1.1 can be satisfied.

According to a preferred embodiment of the first embodiment, the first optical member and the second optical member are joined by optical bonding. Moreover, it is preferable that the optical surface of the first surface side of the second optical member faces the convex surface on the first surface side. Further, the joint surface of the first optical member and the second optical member is preferably planar. Further, when the wavelength of the light used is 300 nm or less, the second optical material is preferably a fluoride.

Further, according to a preferred embodiment of the first embodiment, the first optical material is synthetic quartz, and the second optical material is fluorite. The liquid is pure water. Moreover, it is preferable to provide a liquid immersion prevention device which is provided on the side faces of the first optical member and the second optical member and prevents the liquid from entering the joint surface of the first optical member and the second optical member.

Further, according to a preferred form of the first embodiment, the bonding optical member is held by the second optical member on the lens barrel. At this time, the side surface of the first optical member and the inner side surface of the lens barrel are disposed in close proximity to each other, and the side surface and the inner side surface facing each other are subjected to a water repellency treatment, or preferably the side surface of the first optical member. A waterproof member for preventing liquid intrusion is provided between the inner side surfaces of the facing cylinders.

According to a second aspect of the present invention, there is provided a projection optical system for forming an image of a first surface on a second surface, wherein the projection optical is obtained when a refractive index of a gas in an optical path of the projection optical system is 1. The optical path between the system and the second surface is filled with a liquid having a refractive index larger than 1.1, and the second surface side of the projection optical system is provided with a first optical material and adjacent to the liquid. A bonded optical member comprising an optical member and a second optical member formed of a second optical material.

According to a preferred embodiment of the second aspect, preferably, the liquid immersion prevention device is provided on the side surfaces of the first optical member and the second optical member to prevent the liquid from entering the first optical member and the second optical member. Joint surface. Further, the bonding optical member is preferably held by the second optical member on the lens barrel.

At this time, the side surface of the first optical member and the inner side surface of the lens barrel are disposed in close proximity to each other, and the side surface and the inner side surface facing each other are subjected to a water repellency treatment, or preferably the side surface of the first optical member. A waterproof member for preventing liquid intrusion is provided between the inner side surfaces of the facing cylinders.

According to a third embodiment of the present invention, there is provided an exposure apparatus comprising: an illumination system for illuminating a mask set on a first surface; and a projection optical system of the first form or the second form The image of the pattern formed on the mask is formed on the photosensitive substrate set on the second surface.

In a fourth embodiment of the present invention, an exposure method is provided, comprising: an illumination process for illuminating a photomask set on a first surface; and an exposure process by the first form or In the projection optical system of the second aspect, an image of a pattern formed on the mask is projected onto a photosensitive substrate set on the second surface and exposed.

Effect of the invention

In the imaging optical system caused by the optical interaction of the first surface and the second surface in the present invention, a liquid having a refractive index of more than 1.1 exists in the optical path between the imaging optical system and the second surface (dip) The liquid) can increase the number of openings on the second surface side of the imaging optical system. Further, a boundary lens disposed adjacent to the liquid on the most second surface side is formed as, for example, a first optical member formed of synthetic quartz and adjacent to the liquid, and formed of, for example, fluorite. A bonded optical member formed by joining of the second optical members. With such a configuration, the imaging performance due to the influence of the constriction of the boundary lens can be suppressed, and the optical surface of the boundary lens can be suppressed from being damaged due to the influence of the liquid (liquid) and the imaging performance can be suppressed. Low.

Therefore, the present invention can realize an imaging optical system in which the number of openings on the second face side can be ensured to be large and effective by the presence of a liquid in the optical path between the projection optical system and the second face, and is substantially not subjected to the contraction The effect or immersion liquid does not cause damage and can maintain good imaging performance for a long period of time. As a result, in the exposure apparatus and the exposure method using the imaging optical system of the present invention, projection exposure of high resolution can be stably maintained for a long period of time, thereby producing a good element.

The above and other objects, features and advantages of the present invention will become more <RTIgt;

In the present invention, a liquid having a refractive index of more than 1.1 exists in the optical path between the imaging optical system and the second surface on which the photosensitive substrate is typically disposed, so that the number of openings on the second surface side of the imaging optical system is increased. Increase. By the way, M. Switkes and M. Rothschild, in "SPIE2002 Microlithography", "Resolution Enhancement of 157-nm Lithography by Liquid Im mersion" published by "Massachusetts Institute of Technology", enumerates light below 200 nm. The liquid of the desired transmittance is also referred to as a perfluoropolyether (Perfluoropolyethers: trade name of 3S Corporation of the United States) or deionized water (Deionized Water) as a candidate liquid.

Further, in the imaging optical system (projection optical system) of the present invention, a boundary lens disposed adjacent to the liquid (immersion liquid) on the most image side (second surface side) is formed as, for example, synthetic quartz (No. (1) Optical material) A bonded optical member comprising a first optical member adjacent to the liquid and a second optical member formed of fluorite (second optical material). Here, the first optical member and the second optical member are joined to each other by, for example, optical bonding. In addition, the term "optical bonding" refers to a technique in which the surfaces of two optical members are processed into the same shape with high precision, and the surfaces are brought into close contact with each other without using an adhesive, and the two optical members are joined by the attraction between the molecules.

Further, in the present invention, when the above-described configuration is processed, for example, the first optical member adjacent to the liquid is formed of synthetic quartz and satisfies the following conditional expression (1). In the conditional expression (1), TA is the thickness of the first optical member (the size of the first optical member along the optical axis), and IH is the maximum image height of the image surface (the second surface).

0.1<TA/IH<1.1 (1) FIG. 1 is an image forming performance of the first optical member formed by synthetic quartz and which is adjacent to the immersion liquid in the projection optical system prepared by the typical design method. A schematic illustration of the impact. In Fig. 1, the horizontal axis corresponds to TA/IH in the conditional expression (1), and the vertical axis represents the amount of change in the wavefront aberration (mλRMS) for the amount of deterioration of the received image which is expected five years later. Further, in the unit mλRMS of the vertical axis, λ is the wavelength of light, and RMS (root mean square) is the root mean square.

Further, in the typical design used in Fig. 1, the light used was ArF excimer laser light (λ = 193 nm), the immersion liquid was pure water, the image side opening number was 1.0, and the maximum image height was 13.5. Mm. Referring to Fig. 1, when the upper limit value of the conditional expression (1) is exceeded, if the amount of deterioration of the received image aberration expected five years later is large, the required optical performance cannot be continuously maintained for a long period of time, that is, it cannot be sustained for a long period of time. Maintain good imaging performance.

On the other hand, when it is less than the lower limit of the conditional expression (1), for example, the thickness of the first optical member adjacent to the immersion liquid phase formed by synthetic quartz is small, and the sufficient surface for optical bonding is sufficient. Precision machining is not possible. Further, when the upper limit value of the conditional expression (1) is set to 0.7, even if the irradiation energy is increased, the influence of the contraction can be suppressed, and the high yield and the high resolution can be realized, which is more preferable. In addition, when the lower limit of the conditional expression (1) is set to 0.14, the precision of the machined surface of the first optical member can be increased, and a high resolution can be achieved, which is more preferable.

As described above, in the imaging optical system (projection optical system) of the present invention, for example, the above-described tightening phenomenon does not substantially occur in the second optical member formed of fluorite. On the other hand, for example, in the first optical member formed of synthetic quartz and adjacent to the immersion liquid phase, the shrinkage phenomenon is likely to occur, but in the conditional expression (1), since the thickness TA of the first optical member is set to be sufficiently small, The influence of the contraction in the first optical member can be suppressed to be small. As a result, the imaging performance of the projection optical system due to the influence of the contraction in the boundary lens can be suppressed.

However, when the temperature of the synthetic quartz is easily increased by the light irradiation, when the heat of the first optical member is transferred to the liquid to raise the temperature of the liquid, the refractive index changes, and the imaging performance of the projection optical system is lowered. However, in the present invention, since the thickness TA of the first optical member in the conditional expression (1) is set to be sufficiently small, even if the temperature of the first optical member rises due to light irradiation, the generated heat can be easily easily used, for example. The second optical member composed of fluorite having a large thermal conductivity is sent to the lens barrel. As a result, the heat transferred to the liquid by the first optical member can be suppressed to be small, and the deterioration of the imaging performance of the imaging optical system (projection optical system) due to the refractive index fluctuation of the liquid can be suppressed.

Further, in the present invention, for example, a second optical member formed of fluorite which is easily dissolved in pure water and a liquid such as pure water are formed, for example, of synthetic quartz which is substantially insoluble in pure water. 1 The optical member exists in a sealed state. Therefore, the optical surface of the second optical member is not damaged by the influence of pure water, and the optical surface of the boundary lens is not damaged by the influence of pure water. This maintains good imaging performance of the projection optical system for a long period of time. That is, in the imaging optical system (projection optical system) of the present invention, the effective number of image side openings can be ensured by the liquid in the optical path between the image planes, substantially without being affected by the deflation or by immersion or liquid. The damage can be maintained for a long period of time to maintain good imaging performance of the projection optical system.

In the present invention, in order to increase the number of openings on the second surface side (image side) of the imaging optical system (projection optical system), it is preferable to make the optical surface of the object side (first surface side) of the second optical member. A convex surface on the side of the object. Moreover, in order to achieve good optical joining, the joint surface of the first optical member and the second optical member is preferably planar. Moreover, in order to improve the resolution of the projection optical system, the wavelength used is preferably 300 nm or less. Further, in order to avoid the occurrence of shrinkage, the second optical material used to form the second optical member is preferably a fluoride (for example, fluorite).

Further, under the influence of the photosensitive material eluted in the immersion liquid, the first optical member needs to be replaced when the first optical member is stained or the first optical member is eluted, but the method of the present invention has The advantage is that the mechanism for holding the first optical member in a replaceable manner is simplified. Such an advantage exists even when the first optical material for forming the first optical member and the second optical material for forming the second optical member are the same type of material.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

Fig. 2 is a schematic view showing the configuration of the exposure apparatus in the embodiment of the present invention. 3 is a schematic view showing a configuration from a boundary lens to a wafer in the present embodiment. Further, in Fig. 2, the Z axis is set to be parallel to the optical axis AX of the projection optical system PL, and the Y axis is set to be parallel to the paper surface of Fig. 2 in the inner surface perpendicular to the optical axis AX, and the X axis is set to Vertical to the paper surface of Figure 2.

Referring to Fig. 2, the exposure apparatus of the present embodiment includes, for example, an ArF excimer laser light source as a light source 100 for supplying ultraviolet light to illumination light. The light emitted from the light source 100 is superimposedly irradiated onto the mask R on which the predetermined pattern has been formed via the illumination optical system IL. Further, the optical path between the light source 100 and the illumination optical system IL is sealed by a casing (not shown). The space from the light source 100 to the optical member on the most mask side of the illumination optical system IL is replaced with an inert gas such as helium or nitrogen in a gas having a low absorption rate of exposure light, or is kept at approximately vacuum. status.

The mask R is held in parallel on the reticle stage RS on the XY plane by the reticle support. A pattern to be transferred is formed on the mask R, and the rectangular pattern area is illuminated. The reticle stage RS can be moved in a two-dimensional manner along the reticle surface (ie, the XY plane) by the action of the omitted drive system in the drawing, and the position coordinate is calculated by using the ray mask moving mirror RM interferometer RIF It is measured and constructed to control its position. The light from the pattern formed in the mask R forms a mask image on the wafer W on which the photosensitive substrate is placed via the projection optical system PL.

The wafer W is held in parallel on the wafer table WS in the XY plane by the wafer support table WT. Then, an image is formed on the wafer W in a rectangular effective exposure region to form an optical correspondence with the rectangular illumination region on the mask R. The wafer table WS can be moved in a two-dimensional manner along the wafer surface (ie, the XY plane) by the action of the omitted drive system in the figure, and the position coordinates are obtained by using the interferometer WIF of the wafer moving mirror WM. It is measured and constructed to control its position.

In the exposure apparatus of the present embodiment, the optical member disposed on the most photomask side of the optical member used in the projection optical system PL and the projection between the boundary lens Lb (see FIG. 3) disposed on the most wafer side are formed. The inside of the optical system PL is kept in an airtight state. The gas inside the projection optical system PL is replaced with an inert gas such as helium or nitrogen, or is kept in a state of approximately vacuum. Further, a mask R, a mask table RS, and the like are disposed in a narrow optical path between the illumination optical system IL and the projection optical system PL, and the inside of the casing (not shown) that surrounds the mask R and the mask table RS is sealed. The inert gas such as helium or nitrogen is filled in, or kept in a vacuum state.

Referring to Fig. 3, in the present embodiment, the optical path between the boundary lens Lb on the wafer side of the projection optical system PL and the wafer W is filled with a liquid Lm having a refractive index larger than 1.1. For example, pure water can be used as the liquid Lm for the immersion liquid. Further, the boundary lens Lb is configured by optically joining the first optical member Lb1 formed of synthetic quartz and adjacent to the liquid Lm and the second optical member Lb2 formed of fluorite. Here, the first optical member Lb1 is a parallel plane plate, and the second optical member Lb2 is a plano-convex lens having a convex surface facing the mask side.

Further, the optical path between the boundary lens Lb of the projection optical system PL and the wafer W is continuously filled with the liquid Lm, which can be used, for example, in the technique disclosed in International Publication No. WO99/49504 or in Japanese Laid-Open Patent Publication No. Hei 10-303114. The disclosed technology and the like. In the technique disclosed in International Publication No. WO99/49504, a liquid Lm adjusted to a predetermined temperature is supplied from a liquid supply device via a supply pipe and a discharge nozzle to fill a boundary between the boundary lens Lb and the wafer W. The optical path recovers the liquid from the wafer W via the recovery tube and the inflow nozzle by the liquid supply device.

In the technique disclosed in Japanese Laid-Open Patent Publication No. Hei 10-303114, the wafer support table WT is formed in a container shape so as to accommodate the liquid Lm, and the center (in the liquid) of the inside is determined by vacuum suction to determine the wafer W. The location is maintained. Further, the tip end portion of the barrel of the projection optical system PL reaches the liquid, and the optical surface on the wafer side of the boundary lens Lb reaches the liquid.

As described above, an air which hardly absorbs the exposure light beam is continuously formed in all the optical paths from the light source 100 to the wafer W. Therefore, using the drive system and the interferometer (RIF, WIF), in the plane (XY) orthogonal to the optical axis AX of the projection optical system PL, on the one hand, the wafer W is driven in a binary mode and on the other hand For the overall exposure, the so-called Step and Repeat method, the pattern of the mask R in the short-circuited region of the wafer W is successively exposed.

As described above, in the optical path between the projection optical system PL and the wafer W in which the photosensitive substrate is located, the liquid Lm like pure water exists in the present embodiment. Further, in the projection optical system PL, the boundary lens Lb constitutes a bonding optical member which is joined by the first optical member Lb1 which is formed by synthetic quartz and which is adjacent to the liquid Lm, and the second optical member Lb2 which is formed of fluorite. Formed. Further, the thickness TA of the first optical member Lb1 is set to satisfy the above conditional expression (1).

Therefore, in the projection optical system PL of the present embodiment, the second optical member Lb2 formed of fluorite does not substantially contract. Moreover, since the thickness TA of the first optical member Lb1 formed of synthetic quartz is set to be small, the influence of the contraction in the first optical member Lb1 can be suppressed to be small. As a result, the degradation of the imaging performance of the projection optical system PL can be suppressed by the influence of the contraction in the boundary lens Lb.

Further, in the present embodiment, the second optical member Lb2 formed of fluorite which is easily dissolved in pure water and the liquid Lm formed of pure water are present in a state of being in a state of being insoluble in pure water. The first optical member Lb1 formed of quartz. Therefore, when the optical surface of the second optical member Lb2 is affected by pure water, it is not damaged, and the optical surface of the boundary lens Lb is not damaged by the influence of pure water, and the imaging performance of the projection optical system PL can be improved. It has maintained a good state for a long time.

As described above, in the projection optical system PL of the present embodiment, the liquid Lm exists in the optical path between the wafers W on which the image planes are located to secure an effective number of image side openings, which is caused by the influence of the contraction or the liquid Lm. The damage does not substantially occur and the good imaging performance can be maintained for a long period of time. Therefore, in the exposure apparatus of the present embodiment, a projection optical system PL is used which ensures a large and effective number of image side openings and maintains good imaging performance for a long period of time, and performs high resolution for a long period of time and stably. Projection exposure.

Further, in the projection optical system PL of the present embodiment, the second optical member Lb2 is constituted by a plano-convex lens whose convex surface faces the mask side. When the optical surface on the mask side of the second optical member Lb2 faces the mask side, the number of apertures on the image side can be increased. In addition, since the first optical member Lb1 is formed of a parallel plane plate and the second optical member Lb2 is formed by a plano-convex lens that faces the wafer side in a plane, the joint surface of the first optical member Lb1 and the second optical member Lb2 is planar. Thus a good optical joint can be achieved.

However, when the liquid Lm is immersed in the joint surface of the first optical member Lb1 and the second optical member Lb2 due to capillary action, the first optical member Lb1 and the second optical member Lb2 joined by optical bonding may be joined. Peeling occurred on the surface. Therefore, in the present embodiment, as shown in Fig. 4, for example, an over-coating 41 is formed on the side faces of the first optical member Lb1 and the second optical member Lb2 to prevent the liquid Lm from being immersed thereinto. The liquid infiltration prevention element used for the joint surface of the first optical member Lb1 and the second optical member Lb2.

Further, each optical member (lens or the like) constituting the projection optical system PL must have sufficient strength, and therefore, each of the optical members to be held needs to have a sufficiently large thickness. Further, the light energy during exposure is slightly absorbed in each optical member to become heat. However, if an optical member formed of an optical material having a high thermal conductivity is connected to the lens barrel, the optical member can be thermally conducted toward the lens barrel. The temperature rise is moderated, and heat conduction toward the liquid is suppressed to be small.

According to the above two points, as shown in FIG. 5, in the second optical member Lb2 formed of fluorite having a large thickness and high thermal conductivity, the boundary lens (joining optical member) is used in the present embodiment. Lb is expected to remain on the lens barrel 51. Moreover, with this configuration, when the boundary lens Lb is held by the lens barrel 51, the first optical member Lb1 disposed on the wafer W side and easily contaminated by the lens can be easily replaced.

Further, as described above, since the fluoride is soluble in the water, it is necessary to prevent the intrusion of water until the second optical member Lb2 formed of the fluorite. In the present embodiment, the side surface of the first optical member Lb1 is disposed in close proximity to the inner side surface of the lens barrel 51, and a water repellency treatment is applied to the side surface of the first optical member Lb1 and the inner side surface of the lens barrel 51 which face each other. (For example, when a water-repellent coating layer is formed), the infiltration of pure water can be prevented up to the second optical member Lb2. Alternatively, as shown in FIG. 5, an O-ring 53 is provided between the side surface of the first optical member Lb1 and the inner side surface of the facing lens barrel 51, for example, to prevent penetration of pure water (liquid). Since the waterproof member is used, it is possible to prevent the intrusion of pure water up to the second optical member Lb2.

Further, a water repellency treatment is applied to the side surface of the first optical member Lb1 and the inner surface of the lens barrel 51, and a water repellency treatment (for example, a water repellent coating) may be applied to the side surface of the second optical member Lb2. Further, a waterproof member (for example, an O-ring 53) is provided between the side surface of the first optical member Lb1 and the inner surface of the facing lens barrel 51, and the first optical member shown in FIG. 4 may be provided. An overcoat layer is applied to the side faces of the Lb1 and the second optical member Lb2 as a liquid immersion preventing member. Further, a water repellency treatment may be applied to the side surface of the first optical member Lb1 and the inner surface of the lens barrel 51, and a side may be applied to the side surfaces of the first optical member Lb1 and the second optical member Lb2 shown in FIG. The coating serves as a liquid immersion preventing member.

Further, in the above-described embodiment, the first optical member Lb1 and the second optical member Lb2 are joined by optical bonding. However, the present invention is not limited to this method, and other appropriate methods may be used to join the first optical member Lb1 and the first optical member. 2 optical member Lb2. Further, in the above embodiment, pure water is used as the immersion liquid, but the invention is not limited thereto, and other suitable liquid may be used depending on the wavelength of the light.

Further, in the above embodiment, the first optical member Lb1 is formed of synthetic quartz, and the second optical member Lb2 is formed of fluorite. However, it is not limited thereto, and for example, a suitable optical material having a property substantially insoluble in the immersion liquid may be used to form the first optical member Lb1. Further, for example, a suitable optical material having substantially no shrinkage properties, for example, a suitable fluoride other than fluorite (for example, calcium fluoride, barium fluoride, lithium fluoride, sodium fluoride) may also be used. The bismuth fluoride or the like is formed to form the second optical member Lb2.

Further, in the above-described embodiment, the first optical member Lb1 is formed of a parallel plane plate, and the second optical member Lb2 is formed of a plano-convex lens having a convex surface facing the mask side. However, the present invention is not limited thereto, and various modifications are possible in terms of the shapes of the first optical member Lb1 and the second optical member Lb2. Further, in the above-described embodiment, the configuration is such that one first optical member Lb1 is provided, but the number of the first optical members Lb1 is not limited to one.

In the exposure apparatus of the above-described embodiment, the reticle is illuminated by an illumination device (illumination process), and the transfer pattern formed on the reticle is exposed on the photosensitive substrate by using the projection optical system (exposure) Process), it is possible to manufacture micro-components (semiconductor elements, photographic elements, liquid crystal display elements, thin film magnetic heads, etc.). In the following, an exposure apparatus according to the present embodiment will be described with reference to the flowchart of FIG. 6 by forming a circuit pattern defined in a wafer for a photosensitive substrate or the like to obtain a semiconductor element for a micro device. To illustrate.

First, in step 301 of FIG. 6, a metal film is deposited on one batch of wafers. Next, in step 302, a photoresist is applied to the metal film on the wafer of the batch. Then, in step 303, the exposure apparatus of the present embodiment is used, and the image of the pattern on the mask is sequentially exposed and transferred on each short-circuit area on the wafer by the projection optical system. Then, after the development of the photoresist on the batch of wafers is completed in step 304, in step 305, the photoresist pattern is used as a mask on the batch of wafers to be etched to form a pattern on the mask. Corresponding circuit patterns are formed in each short circuit region on each wafer.

Then, by forming a higher layer circuit and pattern, each element of a semiconductor element or the like is manufactured. According to the above method for manufacturing a semiconductor element, a semiconductor element having a very fine circuit pattern can be obtained in a large amount. Further, in steps 301 to 305, a metal is vapor-deposited on the wafer, a photoresist is coated on the metal film, and then each process of exposure, development, and etching is performed, but before the processes, germanium is formed on the wafer. After the oxide layer, a photoresist is applied to the oxide layer of the crucible, and then the processes of exposure, development, and etching are performed, which is of course possible.

Further, in the exposure apparatus of the present embodiment, a liquid crystal display element for a micro device can be obtained by forming a pattern (a circuit pattern, an electrode pattern, or the like) set on a plate (glass substrate). Hereinafter, an example of the method at this time will be described with reference to the flowchart of Fig. 7 . In Fig. 7, in the pattern forming process 401, the pattern of the mask is transferred to a photosensitive substrate (a glass substrate coated with a photoresist, etc.) using an exposure apparatus of the present embodiment, and exposed to perform a so-called photolithography process. By this photolithography process, a predetermined pattern containing a plurality of electrodes is formed on the photosensitive substrate. Then, the exposed substrate is subjected to respective processes of a developing process, an etching process, a photoresist stripping process, and the like, and a predetermined pattern is formed on the substrate, and then transferred to the next color filter forming process 402.

Next, in the color filter forming process 402, a plurality of groups corresponding to three points of red (R), green (G), and blue (B) are arranged in a matrix, or red (R), green (G). The combination of the three strip-shaped filters of blue (B) is arranged in a plurality of horizontal scanning line directions to form a small color filter. Then, after the color filter forming process 402, a process 403 of combining the units is performed. In the process 403 of combining the units, a substrate having the predetermined pattern obtained by the pattern forming process 401 and a color filter obtained in the color filter forming process 402 are used to combine the liquid crystal panels (liquid crystal unit).

In the process 403 of combining the units, for example, a liquid crystal is injected between a substrate having a predetermined pattern obtained by the pattern forming process 401 and a color filter obtained by the color filter forming process 402. A liquid crystal panel (liquid crystal cell) is manufactured. Then, in the module assembly process 404, various components such as a circuit, a backlight, and the like used in the display operation of the liquid crystal panel (liquid crystal cell) that have been combined are mounted to complete the liquid crystal display element, according to the liquid crystal display element described above. According to the manufacturing method, a liquid crystal display element having a very fine circuit pattern can be obtained in a large amount.

Further, in the above-described embodiment, the ArF excimer laser is used, but the invention is not limited thereto. For example, another appropriate light source such as a KrF excimer laser or an F ₂ laser may be used. Further, in the above-described embodiment, the projection optical system in which the exposure device is mounted is applied to the present invention, but the present invention is not limited thereto, and other general projection optical systems or other general imaging optical systems are also applicable to the present invention.

Further, in the above-described embodiment, although the magnification of the projection optical system is reduced, it is also possible to use an enlarged magnification or an equal magnification when applied to other general imaging optical systems.

Further, as described above, when the liquid immersion method is used, the number NA of openings of the projection optical system is 0.9 to 1.5. When the number NA of openings of such a projection optical system is increased, it is preferable to use polarized illumination because the image forming performance is deteriorated due to the polarizing effect of the scattered polarized light beam used for the exposure beam. At this point, perform a line with the reticle. and. The linear pattern of the spatial pattern of the spatial pattern is matched by the linear polarized illumination, and the pattern of the mask allows the s-polarized component (the component of the polarization direction along the length of the line pattern) to emit a large amount of diffracted light.

In the above-described embodiment, a light-transmitting type reticle having a predetermined light-shielding pattern (or a phase pattern and a light-reducing pattern) formed on a light-transmitting substrate, or a reflection pattern determined on a substrate having a light-reflective property can be used. Instead of the above-mentioned reticle, an optical reticle for forming a pattern or a reflection pattern or a luminescent pattern may be used in accordance with the electronic material of the pattern to be exposed. Such an electronic reticle is disclosed, for example, in U.S. Patent No. 6,778,257. U.S. Patent No. 6,778,257, the disclosure of which is incorporated herein by reference. Further, the concept of the above-described electronic mask includes both a non-light-emitting image display element and a self-style image display element.

While the present invention has been described in its preferred embodiments, the present invention is not intended to limit the invention, and the present invention may be modified and modified without departing from the spirit and scope of the invention. The scope of protection is subject to the definition of the scope of the patent application.

Lb. . . Boundary lens

Lb1. . . First optical member

Lb2. . . Second optical member

Lm. . . Liquid (pure water: immersion liquid)

41. . . Overcoat

51. . . Lens barrel

52. . . Waterproof coating

53. . . O-ring

100. . . Laser source

IL. . . Lighting optical system

R. . . Mask

RS. . . Mask table

PL. . . Projection optical system

W. . . Wafer

WS. . . Wafer table

Fig. 1 is a schematic diagram showing the influence of the contraction of the first optical member formed of synthetic quartz and the immersion liquid phase on the imaging performance of the projection optical system in the projection optical system produced by the typical design.

Fig. 2 is a schematic view showing the configuration of the exposure apparatus in the embodiment of the present invention.

Fig. 3 is a schematic view showing a configuration from a boundary lens to a wafer in the embodiment.

Fig. 4 shows a state in which a coating layer has been formed on the side surfaces of the first optical member and the second optical member.

Fig. 5 shows a state in which the boundary lens is held by the second optical member on the lens barrel.

Fig. 6 is a flow chart showing a method used in the production of a semiconductor element for a micro component.

Fig. 7 is a flow chart showing a method used in the production of a liquid crystal display element for a micro component.

Lb. . . Boundary lens

Lb1. . . First optical member

Lb2. . . Second optical member

Lm. . . Liquid (pure water: immersion liquid)

AX. . . Optical axis of the projection optical system

TA. . . Thickness of the first optical member

W. . . Wafer

Claims (39)

An imaging optical system in which an optical path between the imaging optical system and the second surface is filled when the first surface and the second surface are optically cooperating, and when the refractive index of the air in the optical path of the imaging optical system becomes 1. A liquid having a refractive index larger than 1.1, the imaging optical system including: a first optical member disposed on a most second surface side of the imaging optical system, and a second optical member adjacent to the first optical member And a liquid immersion prevention element for preventing the liquid of the second surface side of the first optical member from entering the second optical member side, wherein the liquid immersion prevention element has a side surface provided on the first optical member The first liquid proofing part on the top. The imaging optical system according to claim 1, wherein the liquid immersion preventing member has an inner side surface opposed to the side surface of the first optical member. The imaging optical system according to claim 2, wherein the liquid immersion preventing member has a second liquid-repellent portion provided on the inner side surface of the member. The imaging optical system according to claim 3, wherein the first liquid-repellent portion and the second liquid-repellent portion are liquid-repellent coating layers. The imaging optical system according to claim 3, wherein the first liquid-repellent portion and the second liquid-repellent portion are isolated from each other. The imaging optical system according to claim 1, wherein the liquid immersion preventing member has an O-ring positioned on a side surface of the first optical member. The imaging optical system according to claim 1, wherein the first optical member and the second optical member are joined to each other by optical bonding. The imaging optical system according to claim 1, wherein the first optical member is formed of synthetic quartz. The imaging optical system of claim 8, wherein the first optical member is a parallel planar plate. The imaging optical system of claim 9, wherein the second optical member is a plano-convex lens. The imaging optical system of claim 1, wherein the second optical member is not adjacent to the liquid. The imaging optical system according to claim 11, comprising a liquid immersion prevention device provided on a side surface of the first optical member and the second optical member to prevent liquid from entering the first optical member and the second optical member. Joint surface. The imaging optical system according to claim 12, wherein the bonding optical member is held on the lens barrel by the second optical member. The imaging optical system according to claim 13, wherein a side surface of the first optical member is disposed adjacent to an inner side surface of the lens barrel, and a water repellency treatment is applied to the side surface and the inner side surface facing each other. The imaging optical system of claim 13, wherein a side surface of the first optical member and an inner side surface of the facing lens barrel are disposed between A waterproof member for preventing the intrusion of a liquid. The imaging optical system according to claim 11, wherein the first optical member and the second optical member are joined by optical bonding. The imaging optical system according to Item 16, wherein the joint surface of the first optical member and the second optical member is planar. The imaging optical system according to claim 11, wherein the optical surface on the first surface side of the second optical member faces the convex surface on the first surface side. The imaging optical system according to claim 11, wherein when the thickness of the first optical member is TA and the maximum image height of the second surface is IH, the condition of 0.1 < TA / IH < 1.1 can be satisfied. The imaging optical system according to claim 11, wherein the second optical material is a material different from the first optical material. In the imaging optical system according to the first aspect of the invention, when the thickness of the first optical member is TA and the maximum image height of the second surface is IH, the condition of 0.1<TA/IH<1.1 can be satisfied. . The imaging optical system according to claim 21, wherein the first optical member and the second optical member are joined by optical bonding. The imaging optical system according to Item 22, wherein the optical surface on the first surface side of the second optical member faces the convex surface on the first surface side. An imaging optical system as described in claim 23, The joint surface of the first optical member and the second optical member is planar. The imaging optical system according to claim 21, wherein the optical surface on the first surface side of the second optical member faces the convex surface on the first surface side. The imaging optical system according to claim 21, wherein the light used has a wavelength of 300 nm or less, and the second optical material is fluoride. The imaging optical system according to claim 26, wherein the first optical material is synthetic quartz, the second optical material is fluorite, and the liquid is pure water. The imaging optical system according to claim 21, further comprising a liquid immersion prevention device provided on a side surface of the first optical member and the second optical member to prevent liquid from entering the first optical member and the second optical member Joint surface. The imaging optical system according to claim 21, wherein the bonding optical member is held on the lens barrel by the second optical member. The imaging optical system according to claim 29, wherein a side surface of the first optical member is disposed adjacent to an inner side surface of the lens barrel, and a water repellency treatment is applied to the side surface and the inner side surface facing each other. The imaging optical system according to claim 29, wherein a waterproof member for preventing immersion of liquid is provided between a side surface of the first optical member and an inner side surface of the facing lens barrel. The imaging optical system according to any one of claims 1 to 31, wherein the optical system is an image in which the first surface is formed Projection optics on 2 sides. An exposure apparatus comprising the imaging optical system according to claim 32, wherein the imaging optical system forms an image of the pattern set on the first surface on the photosensitive substrate set on the second surface. The exposure apparatus of claim 33, further comprising an illumination system for illuminating the mask set on the first surface. An exposure apparatus comprising the imaging optical system according to claim 32, wherein the imaging optical system forms an image of the pattern set on the first surface on the photosensitive substrate set on the second surface. The exposure apparatus of claim 35, wherein the first optical member is a parallel flat plate. The exposure apparatus of claim 36, wherein the second optical member is a plano-convex lens. An exposure method comprising: an illumination process for illuminating a photomask set on a first side; and an exposure process for illuminating the photomask by the imaging optical system of claim 32 The image of the pattern formed thereon is projected on the photosensitive substrate set on the second surface and exposed. A component manufacturing method, comprising: a supply process for supplying a predetermined pattern; and an exposure process for projecting an image of the pattern on the second surface by the imaging optical system of claim 32 Exposure was performed on the set photosensitive substrate.