JP2006349946A - Optical element holding device, lens barrel, exposure apparatus, and method for manufacturing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical element holding device and a lens barrel which can effectively suppress distortion in an optical element by temperature changes, the gravity of the optical element, external impact or the like, and to provide an exposure apparatus and a method for manufacturing a device for efficiently manufacturing a device with a high integration degree in a high yield. <P>SOLUTION: A plurality of slits 36a to 36c penetrating in a direction parallel to the optical axis of a lens 28 are formed in a frame body 32 so as to segment a mounting section 34 in a convex form in a plan view. The mounting section 34 is linked to the frame body 32 as displaceable in a radial direction of the lens 28 via a plurality of pairs of notch springs 37a, 37b in a thin plate form. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical element holding device for holding optical elements such as lenses and mirrors. The present invention also relates to a lens barrel having at least one optical element. Furthermore, the present invention relates to an exposure apparatus used in a manufacturing process of a device such as a semiconductor element, a liquid crystal display element, or a thin film magnetic head, and a manufacturing method of the device.

  The optical system in this type of exposure apparatus is strictly optically adjusted, and optical elements such as lenses and mirrors constituting the optical system are held by a precisely processed optical element holding device. Also, when assembling, storing, transporting, and operating the exposure apparatus of the optical system, the individual optical elements are affected by temperature changes and external forces such as gravity and impact applied to both the individual optical elements and the optical system. It is necessary to reduce the distortion as much as possible.

  Here, each lens of the projection optical system constituting an important part of the exposure apparatus is generally accommodated in a lens barrel in a state of being attached to a lens cell. This lens cell has mechanical problems that occur during the assembly of the projection optical system (for example, transmission of impact applied to the lens barrel to the lens) and mechanical problems that may occur due to temperature changes (for example, expansion and contraction of the lens). ) May be designed to eliminate this.

  For example, in semiconductor elements, circuit patterns have been increasingly miniaturized in accordance with recent high integration demands. For this reason, in an exposure apparatus for manufacturing a semiconductor, there is an increasing demand for further improvement in exposure accuracy and higher resolution, and a technique for keeping the optical surface of an optical element in a good state is becoming more important.

As a lens holding device having a structure for solving various mechanical problems acting on such a lens, for example, the lens is provided with three receivers disposed on a cantilever-type bent portion formed in a lens cell. A material bonded to a seat position has been proposed (see Patent Document 1). In this conventional configuration, the expansion and contraction of the lens cell and the lens caused by the temperature change are absorbed by the bending of the cantilever bending portion, so that the lens is not distorted by mechanical stress.
US Pat. No. 4,733,945

  However, in the above-described conventional configuration, one cantilever bent portion supports the receiving seat to which the lens is bonded with a cantilever structure. For this reason, the rigidity in the optical axis direction of the lens tends to be insufficient at the bent portion of the cantilever, and the bent portion of the cantilever is easily subjected to torsional stress due to a load in the optical axis direction (for example, the weight of the lens itself). This reduces the natural frequency of the cantilever bend, which may increase undesirable lens vibrations and distortion of optical properties in some cases.

  The present invention has been made paying attention to such problems existing in the prior art. An object of the present invention is to provide an optical element holding device and a lens barrel that can effectively suppress the occurrence of distortion of the optical element due to temperature change, the weight of the optical element itself, external impact, and the like.

  Another object is to provide an exposure apparatus and a device manufacturing method capable of manufacturing a highly integrated device efficiently and with a high yield.

  In order to achieve the above object, the invention according to claim 1 is an optical element holding device that holds an optical element, and includes a frame body and a holding portion provided in the frame body. A mounting portion for mounting a peripheral portion of the optical element; and a tangential direction of the optical element, or extending in a direction intersecting the tangential direction of the optical element with a predetermined angle, and the radial direction of the optical element And a plurality of elastically deforming portions that are provided so as to be separated from each other by a predetermined distance and connectably displaceable in the radial direction of the optical element.

  According to the first aspect of the present invention, when the optical element expands and contracts due to a temperature change, the plurality of elastic deformation portions are displaced in the radial direction of the optical element, so that the expansion or contraction of the optical element is absorbed. For this reason, in the optical element holding device, the occurrence of distortion of the optical element due to temperature change, the weight of the optical element itself, and external impact is effectively suppressed. Accordingly, it is possible to reduce the influence on the optical element due to the state change during use, and to keep the optical performance stable.

  According to a second aspect of the present invention, in the first aspect of the present invention, the elastically deforming portion is a thin plate having a length substantially equal to that of the mounting portion in the optical axis direction of the optical element. It has an elastic deformation piece, It is characterized by the above-mentioned.

  In the invention according to the second aspect, in addition to the action of the invention according to the first aspect, in the optical axis direction of the optical element while ensuring sufficient elastic deformation in the radial direction of the optical element in the elastic deformation piece. The rigidity of the optical element can be further increased, and the optical element can be held more stably.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the elastically deforming portion is arranged on one side and the other side of the placing portion with respect to the tangential direction or the intersecting direction. It has a pair of elastic deformation pieces provided.

  In the invention according to claim 3, in addition to the action of the invention according to claim 1 or 2, the mounting portion is supported by a pair of elastic deformation pieces in a doubly supported structure, and the elastic deformation portion The rigidity in the optical axis direction of the optical element is significantly increased.

  The invention according to claim 4 is the invention according to claim 3, wherein the placement portion is defined by a slit that penetrates the frame body in the optical axis direction of the optical element, and the elastic deformation piece. Comprises a leaf spring partitioned by a slit penetrating the frame body in the optical axis direction of the optical element.

  According to the fourth aspect of the present invention, the effect of the third aspect of the invention can be achieved with a simple configuration. In addition, the frame, the elastically deformable piece, and the mounting portion can be configured as an integral member, and the number of parts and the number of assembly steps in the optical element holding device can be reduced.

  The invention according to claim 5 is the invention according to claim 3 or 4, wherein the support point of the optical element in the mounting portion is substantially equal to the support rigidity of the optical element by each of the elastic deformation pieces. It is characterized by being formed on a neutral axis that is equal.

  In the invention according to claim 5, in addition to the operation of the invention according to claim 3 or 4, the rotational moment about the tangential direction of the optical element generated when the optical element is placed on the placement portion is Can be small. For this reason, it becomes possible to reduce the torsional stress in the optical axis direction of the optical element generated in the mounting portion, and the optical element can be held more stably.

  According to a sixth aspect of the present invention, in the invention according to any one of the second to fifth aspects, the thickness of each of the elastic deformation pieces in the radial direction of the optical element is uniform. It is a feature.

In the invention according to claim 6, in addition to the action of the invention according to any one of claims 2 to 5, the structure is simple and the elastic deformation piece can be easily processed. .
The invention according to claim 7 is the invention according to any one of claims 3 to 6, wherein the pair of elastic deformation pieces on the optical element side and the pair of elastic deformations on the frame body side. The piece is connected to the mounting portion at a position shifted in a tangential direction of the optical element.

  In the invention according to claim 7, in addition to the action of the invention according to any one of claims 3 to 6, the distance between the pair of outer elastic deformation pieces is smaller than that of the pair of inner elastic deformation pieces. By arranging in such a manner, the elastically deformable portion can be reduced in size, and as a result, the frame can be reduced in size even in the case of an annular frame.

  According to an eighth aspect of the present invention, in a lens barrel that holds a plurality of optical elements, at least one of the optical elements is interposed via the optical element holding device according to any one of the first to seventh aspects. It is characterized by being held.

In the eighth aspect of the invention, since the optical performance of each optical element is maintained high, the change in the optical performance of the entire optical system accommodated in the lens barrel is greatly reduced.
The invention according to claim 9 is an exposure apparatus that exposes a substrate with exposure light that passes through a plurality of optical elements, wherein at least one of the plurality of optical elements is any one of claims 1 to 7. It is characterized in that it is held via the optical element holding device described in 1. above.

  In the ninth aspect of the invention, since the optical performance of the optical element is kept high, the exposure accuracy of the exposure apparatus is improved. For this reason, it is possible to manufacture a highly integrated device efficiently and with a high yield.

  The invention according to claim 10 is the invention according to claim 9, wherein the plurality of optical elements constitute a projection optical system that projects an image of a pattern formed on a mask onto the substrate. It is characterized by.

  In the invention according to the tenth aspect, in addition to the action of the invention according to the ninth aspect, an unexpected distortion is suppressed in the image of the pattern passing through the projection optical system. This is particularly effective when exposure is performed using a mask having the same.

  According to an eleventh aspect of the present invention, in the device manufacturing method including a lithography step, the lithography step uses the exposure apparatus according to the ninth or tenth aspect.

According to the eleventh aspect of the present invention, a highly integrated device can be efficiently manufactured with a high yield.
Next, technical ideas further included in the inventions described in the above claims will be described below together with their actions.

(1) The optical element holding device according to claim 1, wherein the frame, the holding block, and the elastically deforming portion are formed as an integral member.
Therefore, according to the invention described in (1), there is an effect that the number of parts and the number of assembly steps in the optical element holding device can be reduced.

  As described above in detail, according to the present invention, an optical element holding device and a lens barrel capable of effectively suppressing the occurrence of distortion of the optical element due to temperature change, the weight of the optical element itself, external impact, etc. Can be provided. Further, it is possible to provide an exposure apparatus and a device manufacturing method capable of manufacturing a highly integrated device efficiently and with a high yield.

(First embodiment)
The exposure apparatus, the optical element holding apparatus, and the lens barrel of the present invention are described below. For example, an exposure apparatus for manufacturing a semiconductor element, an optical element holding apparatus that holds an optical element such as a lens, and a mirror that houses a projection optical system. A first embodiment embodied in a cylinder will be described with reference to FIGS.

  FIG. 1 is a view showing a schematic configuration of the exposure apparatus 21. As shown in FIG. 1, an exposure apparatus 21 includes a light source 22, an illumination optical system 23, a reticle stage 24 that holds a reticle R as a mask, a projection optical system 25, and a wafer that holds a wafer W as a substrate. The stage 26 is comprised.

  The light source 22 is an ArF excimer laser light source. The illumination optical system 23 includes an unillustrated optical integrator such as a relay lens, fly-eye lens, and rod lens, various lens systems such as a condenser lens, an aperture stop, and the like. Then, the exposure light EL emitted from the light source 22 passes through the illumination optical system 23 and is adjusted so as to uniformly illuminate the pattern on the reticle R.

  The reticle stage 24 is arranged below the illumination optical system 23, that is, on the object plane side of the projection optical system 25 described later, so that the mounting surface of the reticle R is substantially orthogonal to the optical axis direction of the projection optical system 25. Has been. The projection optical system 25 is configured to accommodate and hold a plurality of lenses 28 as optical elements through a lens cell 29 as an optical element holding device in a lens barrel 27. The wafer stage 26 is disposed on the image plane side of the projection optical system 25 so that the mounting surface of the wafer W intersects the optical axis direction of the projection optical system 25. Then, the image of the pattern on the reticle R illuminated by the exposure light EL is projected and transferred onto the wafer W on the wafer stage 26 in a state of being reduced to a predetermined reduction magnification through the projection optical system 25. It has become.

Next, the detailed configuration of the lens cell 29 will be described.
FIG. 2 is a partially broken perspective view showing the lens cell 29. As shown in FIG. 2, the lens 28 is made of a glass material such as synthetic quartz or fluorite, and a flange portion 28a is formed on the periphery thereof. The lens cell 29 includes a frame body 32 that constitutes a part of the lens barrel 27 and three holding portions 33 that are disposed on the frame body 32 at equal angular intervals. The frame body 32 is formed in an annular shape from a metal material, and a plurality of the frame bodies 32 are stacked to form one lens barrel 27. These holding portions 33 hold the flange portion 28a of the lens 28.

  FIG. 3 is a perspective view showing the holding portion 33, and FIG. 4 is an exploded perspective view showing the holding portion 33. As shown in FIG. 3 and FIG. 4, the holding portion 33 is roughly provided with a placement portion 34 and a clamp member 35.

  FIG. 5 is a partial plan view of the frame body 32 around the mounting portion 34. In FIG. 5, in order to facilitate understanding, the cutout springs 37 a and 37 b are drawn with the thickness T increased.

  As shown in FIG. 5, the frame 32 is formed with a plurality of slits 36a to 36c penetrating in a direction parallel to the optical axis of the lens 28 by wire electric discharge machining. A convex-shaped mounting portion 34 is partitioned. Due to the presence of the plurality of slits 36 a to 36 c, the mounting portion 34 is notched springs 37 a and 37 b as a plurality of pairs (two pairs in this embodiment) of elastic deformation pieces that form a thin plate shape with respect to the frame body 32. The lens 28 is connected so as to be displaceable in the radial direction of the lens 28.

  Here, the mounting portion 34 and the notch springs 37a and 37b are both formed integrally with the frame body 32 (with one member), and the relative displacement of the lens 28 and the frame body 32 in the radial direction of the lens 28 is determined. An elastic deformation portion 38 having an allowable tangent bar structure is formed. The notch springs 37 a and 37 b are formed so as to extend in the tangential direction of the lens 28 from the side surfaces 34 a and 34 b of the mounting portion 34 in a plane orthogonal to the tangential direction of the lens 28.

  A concave portion 39 is formed on the inner peripheral side of the mounting portion 34 so as not to interfere with the outer peripheral edge of the flange portion 28 a of the lens 28. A seat surface block 41 having a seat surface 40 that supports the flange portion 28 a of the lens 28 is formed in the center of the recess 39. The seat surface 40 is formed so that the center thereof is positioned on the neutral axis NA where the support rigidity of the mounting portion 34 by the notch spring 37a and the notch spring 37b is substantially equal.

  6 is a cross-sectional view taken along line 6-6 of FIG. 5 and is a partial cross-sectional view of the lens cell 29 with the holding portion 33 as the center. As shown in FIG. 6, the seating surface 40 is formed so as to be approximately half the height of the mounting portion 34 in the optical axis direction of the lens 28. Further, as shown in FIG. 5, the notch spring 37a and the notch spring 37b are formed to have the same thickness T, so that the neutral axis NA has the notch spring 37a and the notch spring 37b. Is an axis that extends in the tangential direction of the lens 28 and passes through approximately half the thickness of the mounting portion 34 in the optical axis direction of the lens 28.

As shown in FIG. 4, the clamp member 35 is disposed above the seat block 41 and includes a clamp body 42 and a pad member 43.
The clamp body 42 includes a pressing surface block 44, an attachment portion 45 for attaching to the frame body 32, and an arm portion 46 that connects the pressing surface block 44 and the attachment portion 45. The pressing surface block 44, the attachment portion 45, and the arm portion 46 are integrally formed.

  A pressing surface 47 is formed on the lower surface of the pressing surface block 44 so as to face the seating surface 40 of the seating surface block 41. The attachment portion 45 and the pressing surface block 44 are separated from each other with a predetermined interval. The clamp member 35 is fixed to the frame body 32 by fastening the attachment portion 45 with the bolt 48 in a state where the attachment portion 45 is joined to the frame body 32 via the pad member 43.

  A pair of arm portions 46 are provided so as to connect both ends of the pressing surface block 44 and the attachment portion 45. Each arm portion 46 is formed in a U-shape in a plane, and is formed with a length that can be elastically deformed in a state where the attachment portion 45 is joined to the frame body 32 via the pad member 43.

  The pad member 43 includes a clamping portion 49 that is sandwiched between the attachment portion 45 of the clamp body 42 and the frame body 32, and an action portion that is interposed between the pressing surface 47 and the upper surface of the flange portion 28a of the lens 28. 50, and a thin plate portion 51 that connects the clamping portion 49 and the action portion 50 and is elastically deformable. On the lower surface of the action portion 50, an action surface 52 that engages with the upper surface of the flange portion 28 a of the lens 28 is formed in a flat shape so as to correspond to the seat surface 40 of the seat surface block 41.

  As shown in FIG. 6, the clamp member 35 configured as described above is configured such that the arm portion 46 of the clamp main body 42 is elastically deformed by tightening the bolt 48, and the pressing surface 47 of the pressing surface block 44. A pressing force is applied to the seat block 41 side. This pressing force acts on the upper surface of the flange portion 28 a of the lens 28 via the action surface 52 of the pad member 43. Accordingly, the flange portion 28 a of the lens 28 is sandwiched between the seat surface 40 of the seat surface block 41 and the pressing surface 47 of the pressing surface block 44.

  FIG. 7 is a plan view showing a specific configuration of the weight support mechanisms 53 arranged on the frame body 32 between the adjacent holding portions 33. The number of weight support mechanisms 53 is set according to at least one of the weight, thickness, diameter, shape, material, and number of holding portions 33 of the lens 28. Incidentally, in this embodiment, three weight support mechanisms 53 are disposed between the holding parts 33 adjacent to each other.

  As shown in FIG. 7, each weight support mechanism 53 is configured by a support plate spring 55 disposed in a notch 54 that is recessed in the lower surface side of the frame body 32. The support plate spring 55 includes a contact portion 56 that contacts the lower surface of the flange portion 28 a of the lens 28, a pair of support portions 58 that are attached and supported to the frame body 32 by a pair of bolts 57, a contact portion 56, and a support. A pair of bent portions 59 that connect the portions 58 are provided. A part of the weight of the lens 28 is supported by the elastic action of the support plate spring 55.

  By the way, when the mounting portion 34 is supported by a plurality of pairs of notch springs 37a and 37b as in the present embodiment, the lens 28 when the lens 28 in the entire notch springs 37a and 37b is thermally deformed. It is necessary to set the reaction force acting on the same as or less than the case where the reaction force is supported by the pair of notch springs. FIG. 8 is an explanatory diagram relating to a method of setting the thicknesses of a plurality of pairs of notch springs 37a and 37b that generate a reaction force equivalent to the case where the mounting portion 34 is supported by a pair of notch springs having a thickness h. .

Here, as shown in FIG. 8, when a predetermined force in the radial direction of the lens 28 is applied to the mounting portion 34, the cross-sectional secondary moment I generated in the notch spring is set to be constant. And The cross-sectional secondary moment I is obtained by the following equation.

^{I = bh 3/12 ...... (} 1)
In addition, b is the length of the lens 28 in the optical axis direction of the notch spring.
h is the thickness of the notch spring in the radial direction.

Here, since the length of each notch spring in the optical axis direction is constant, b can be treated as a constant. Then, from the above (1), when it is determined how many times the thickness h of the pair of notch springs in the plurality of pairs of notch springs should be obtained, the following is obtained. .

Reaction force in the case of two pairs, notches spring 37a, the thickness of 37b, ^1/3 √2 times that of the pair (≒ 0.794 times), that is roughly if 0.8 h, giving the lens 28 Are almost equivalent. In this case, the total thickness (total thickness) of the two pairs of notch springs 37a and 37b is approximately 1.6h at 1.588h. For this reason, the mounting portion 34 can be supported by the notch springs 37a and 37b having a total thickness of 1.6h while keeping the reaction force applied to the lens 28 almost equal, and the lens 28 can be moved in the optical axis direction. It becomes possible to hold in a more stable state.

Hereinafter, the thicknesses of three or more pairs of notch springs are listed as follows.
Thickness of one sheet Total thickness In case of 3 pairs: ^1/3 √3 times 0.693h 2.079h
In the case of 4-to-: ^1/3 √4 times 0.630h 2.520h
In the case of 5 pairs: ^1/3 √5 times 0.693h 2.925h
Therefore, as the number of notch springs increases, the support rigidity in the optical axis direction of the lens 28 in the mounting portion 34 increases.

Therefore, according to the present embodiment, the following effects can be obtained.
(A) In this lens cell 29, the lens 28 extends from the mounting portion 34 on which the flange portion 28a of the lens 28 is mounted in the tangential direction of the lens 28, and is provided at a predetermined interval in the radial direction of the lens 28. A plurality of notch springs 37 a and 37 b are provided to connect the lens 34 so as to be displaceable in the radial direction of the lens 28.

  For this reason, when the lens 28 expands or contracts due to a temperature change, the notch springs 37a and 37b are displaced in the radial direction of the lens 28, so that the expansion or contraction of the lens 28 is absorbed. Here, since the mounting portion 34 is supported by the plurality of notch springs 37a and 37b, the support rigidity in the optical axis direction of the lens 28 in the elastic deformation portion 38 is increased. Thereby, in the lens cell 29, the generation | occurrence | production of the distortion of the lens 28 by the temperature change, the weight of lens 28 itself, and the impact from the outside can be suppressed effectively. Accordingly, it is possible to reduce the influence caused by the state change during use of the lens 28 and to keep the optical performance of the lens 28 stable.

(A) In the lens cell 29, the notch springs 37 a and 37 b have a thin plate shape, and have substantially the same length as the mounting portion 34 in the optical axis direction of the lens 28.
For this reason, it is possible to further increase the rigidity of the lens 28 in the optical axis direction while ensuring sufficient elastic deformation in the radial direction of the lens 28 at the notch springs 37a and 37b, and to hold the lens 28 more stably. can do.

  (C) In the lens cell 29, the notch springs 37a and 37b are formed so as to form a pair from the side surface 34a on one side and the side surface 34b on the other side of the mounting portion 34 in the tangential direction of the lens 28. Yes.

  For this reason, the mounting portion 34 is supported by a notch spring 37a, 37b in a double-supported structure, and is supported by a plurality of pairs of notch springs 37a, 37b. Thereby, the support rigidity in the optical axis direction of the lens 28 in the elastic deformation portion 38 is remarkably enhanced, and the occurrence of distortion of the lens 28 due to the weight of the lens 28 itself and the external impact in the lens cell 29 is effectively suppressed. be able to.

  (D) In this lens cell 29, the mounting portion 34 is partitioned by slits 36 a to 36 c that penetrate the frame body 32 in the optical axis direction of the lens 28, and the notch springs 37 a and 37 b are separated from the frame body 32. The leaf spring is defined by slits 36 a to 36 c that penetrate the lens 28 in the optical axis direction.

  For this reason, in the lens cell 29, the effects described in (A) to (C) can be exhibited with a simple configuration. Further, the frame body 32, the notch springs 37a and 37b, and the mounting portion 34 can be configured as an integral member, and the number of parts and assembly man-hours in the lens cell 29 can be reduced.

  (E) In this lens cell 29, the center of the seating surface 40 of the lens 28 in the mounting portion 34 is formed on the neutral axis NA where the support rigidity of the lens 28 by each of the notch springs 37a and 37b is substantially equal. Yes.

  For this reason, it is possible to reduce the rotational moment about the tangential direction of the lens 28 generated when the lens 28 is placed on the placement portion 34. Accordingly, it is possible to reduce the torsional stress in the optical axis direction of the lens 28 generated in the mounting portion 34, and it is possible to hold the lens 28 more stably.

(F) In the lens cell 29, the thicknesses of the notches springs 37a and 37b in the radial direction of the lenses 28 are uniform.
Therefore, the configuration of the lens cell 29 is simplified, and the cutout springs 37a and 37b can be easily processed.

  (G) In the lens cell 29, one of the notch springs 37a and 37b disposed on both sides of the mounting portion 34 is connected to one side surface 34a of the mounting portion 34, and the other is the mounting portion. 34 is connected to a side surface 34b opposite to the side surface 34a.

For this reason, the structure of the elastic deformation part 38 can be simplified and the process of the elastic deformation part 38 can be performed easily.
(H) In the lens barrel 27, a plurality of lenses 28 are held via a lens cell 29 having the excellent effects (A) to (G).

For this reason, since the optical performance of each lens 28 can be maintained high, a change in the optical performance of the entire projection optical system 25 accommodated in the lens barrel 27 can be greatly reduced.
(K) In this exposure apparatus 21, a lens 28 through which exposure light passes is held via a lens cell 29 having the excellent effects (A) to (G).

  Therefore, the optical performance of each lens 28 can be kept high, the exposure accuracy of the exposure apparatus 21 can be improved, and a highly integrated device can be manufactured efficiently and with a high yield.

  (G) In this exposure apparatus 21, the lens 28 constituting the projection optical system 25 that projects the image of the pattern formed on the reticle R onto the wafer W has the excellent effects (A) to (G). The lens cell 29 is held through.

  For this reason, it is possible to prevent unexpected distortion from occurring in the pattern image passing through the projection optical system 25. Here, since the exposure accuracy in the exposure apparatus 21 greatly depends on the optical performance of the projection optical system 25, exposure is performed using a reticle R having an extremely fine pattern as in the exposure apparatus 21 for manufacturing semiconductor elements. This is particularly effective when

(Second Embodiment)
Next, a second embodiment of the present invention will be described with a focus on differences from the first embodiment.

  In the second embodiment, as shown in FIG. 9, the configuration of the notch springs 37a and 37b is different from that of the first embodiment. That is, the notch springs 37 a and 37 b are arranged so as to be shifted in the tangential direction of the lens 28.

  Further, the thickness T1 in the radial direction of the notch spring 37a is different from the thickness T2 in the radial direction of the lens 28 of the notch spring 37b. Here, the thickness T1 of the notch spring 37a on the lens 28 side is thicker than T2, and the thickness T2 of the outer notch spring 37b is thinner than T1.

  In this case, the neutral axis NA at which the support rigidity of the mounting portion 34 by the notch spring 37a and the notch spring 37b is substantially equal is the center line CA1 of the notch spring 37a and the center line CA2 of the notch spring 37b. It will be located in the middle. That is, the distance d between the neutral axis NA and the center line CA1 of the notch spring 37a is equal to the distance d between the neutral axis NA and the center line CA2 of the notch spring 37b.

  When the reaction force acting on the lens 28 is increased when the lens 28 is thermally deformed by increasing the thickness T1 of the notch spring 37a, the notch spring 37a is moved in the tangential direction of the lens 28. The reaction force may be reduced by forming the length L1 to be longer than the length L2 of the notch spring 37b in the tangential direction of the lens 28.

Therefore, according to the present embodiment, the following effects can be obtained in addition to the effects described in (a) to (e) and (c) to (k) in the first embodiment.
(S) In the lens cell 29, the notch spring 37 a on the lens 28 side and the notch spring 37 b on the frame body 32 side are connected to the mounting portion 34 at a position shifted in the tangential direction of the lens 28. Yes.

  For this reason, each notch spring 37b on the outer side can be arranged so that the interval is narrower than that on each notch spring 37a on the inside, and the elastic deformation portion 38 can be reduced in size. As a result, the annular frame 32 can be thinned in the radial direction of the lens 28, and the frame 32 can be downsized.

(Modification)
The embodiment of the present invention may be modified as follows.
In the first embodiment, the thicknesses of the notch springs 37a and 37b in the radial direction of the lens 28 may be different from each other. In this case, for example, when the two pairs of notch springs 37a and 37b have the same length in the tangential direction of the lens 28 and have different thicknesses, the mounting portion 34 formed by the notch spring 37a and the notch spring 37b. The neutral axis NA at which the support rigidity is substantially equal moves to the notch spring side having a large thickness. For this reason, it is preferable to provide the seat surface 40 on the moved neutral axis NA.

Further, the position of the neutral axis NA may be adjusted by making the lengths in the optical axis direction of the notch springs 37a and 37b having different thicknesses.
In the first embodiment, the notch springs 37 a and 37 b may be arranged so as to be shifted in the tangential direction of the lens 28.

  In each of the above embodiments, the notch springs 37a and 37b are set in the radial direction of the lens 28 only on one side 34a or the other side 34b of the mounting portion 34 with respect to the tangential direction of the lens 28. You may make it provide in intervals.

In each of the above-described embodiments, the notch springs 37a and 37b may be formed so as to be oblique, for example, so as to intersect the tangent line of the lens 28.
In each of the above embodiments, at least one of the notch springs 37 a and 37 b and the placement portion 34 may be formed of a member separate from the frame body 32.

In each of the above embodiments, the mounting portion 34 may be formed in, for example, a substantially semi-circular shape on a plane, a substantially semi-elliptical shape on a plane, a substantially triangular shape on a plane, a flat trapezoidal shape, or the like.
-In each said embodiment, it is good also considering the number of notch springs as 3 or more pairs.

  In each of the above embodiments, the notch springs 37a and 37b are formed to have the same length as the optical axis direction of the lens 28 of the mounting portion 34, but are shorter than the length of the lens 28 of the mounting portion 34 in the optical axis direction. You may form so that it may become.

  In each of the above embodiments, the optical element holding device of the present invention is embodied in the lens cell 29 that holds the lens 28. On the other hand, the optical element holding device of the present invention holds other optical elements such as a mirror, a half mirror, a parallel plate, a prism, a prism mirror, a rod lens, a fly-eye lens, a phase difference plate, and a diaphragm plate. It may be embodied in an optical element holding device.

  The optical element holding device according to the present invention is not limited to the holding configuration of the horizontally placed lens 28 in the projection optical system 25 of the exposure apparatus 21 of the above-described embodiment. For example, the optical element holding apparatus in the illumination optical system 23 of the exposure apparatus 21 You may embody in the holding structure of an element, and the holding structure of a vertical installation type optical element. Furthermore, the present invention may be embodied in a configuration for holding an optical element in another optical machine, for example, an optical system such as a microscope or an interferometer.

  In each of the embodiments, the pressing surface block 44 is configured to press the flange portion 28 a of the lens 28 via the pad member 43. On the other hand, the pad member 43 may be omitted, and the pressing surface block 44 may directly press the flange portion 28a.

  -In the clamp main body 42 of each said embodiment, the arm part 46 extended long is urging | biasing the pressing surface block 44. As shown in FIG. On the other hand, instead of the arm portion 46, for example, a plate-like plate spring, a coil spring, or the like may be employed to urge the holding surface block 44.

  In each of the above-described embodiments, the weight support mechanism 53 is configured by the support plate spring 55 including the contact portion 56, the support portion 58, and the bent portion 59. You may comprise by the simple shape leaf | plate spring provided only with 56 and the support part 58. FIG. Further, the weight support mechanism 53 may be omitted.

Even in the case described above, substantially the same effect as that of the above embodiment can be obtained.
In addition, as an exposure apparatus, a contact exposure apparatus that exposes the mask pattern by bringing the mask and the substrate into close contact without using a projection optical system, and a proximity exposure that exposes the mask pattern by bringing the mask and the substrate close to each other. It can also be applied to the optical system of the apparatus. The projection optical system is not limited to the total refraction type, but may be a catadioptric type or a total reflection type.

Furthermore, the exposure apparatus of the present invention is not limited to a reduction exposure type exposure apparatus, and may be, for example, a 1X exposure type or an expansion exposure type exposure apparatus.
Further, in order to manufacture reticles or masks used in not only microdevices such as semiconductor elements but also light exposure apparatuses, EUV exposure apparatuses, X-ray exposure apparatuses, and electron beam exposure apparatuses, a mother substrate is used as a glass substrate, The present invention can also be applied to an exposure apparatus that transfers a circuit pattern to a silicon wafer or the like. Here, in an exposure apparatus using DUV (deep ultraviolet) or VUV (vacuum ultraviolet) light, a transmission type reticle is generally used. As the reticle substrate, quartz glass, fluorine-doped quartz glass, fluorite, fluoride, and the like are used. Magnesium or quartz is used. In proximity-type X-ray exposure apparatuses and electron beam exposure apparatuses, a transmission type mask (stencil mask, member mask) is used, and a silicon wafer or the like is used as a mask substrate.

  Of course, not only for exposure devices used for manufacturing semiconductor devices, but also for manufacturing exposure devices, thin film magnetic heads, etc., which are used for manufacturing displays including liquid crystal display elements (LCD), etc., to transfer device patterns onto glass plates. The present invention can also be applied to an exposure apparatus that is used to transfer a device pattern to a ceramic wafer or the like, and an exposure apparatus that is used to manufacture an image sensor such as a CCD.

  Furthermore, the present invention provides a scanning stepper that transfers the mask pattern to the substrate while the mask and the substrate are relatively moved, and sequentially moves the substrate to the substrate. The mask pattern is transferred to the substrate while the mask and the substrate are stationary. The present invention can be applied to any step-and-repeat stepper that transfers and sequentially moves the substrate stepwise.

  As the light source of the exposure apparatus, for example, g-line (436 nm), i-line (365 nm), KrF excimer laser (248 nm), F2 laser (157 nm), Kr2 laser (146 nm), Ar2 laser (126 nm), etc. are used. May be. In addition, a single wavelength laser beam in the infrared region or visible region oscillated from a DFB semiconductor laser or fiber laser is amplified by, for example, a fiber amplifier doped with erbium (or both erbium and ytterbium), and a nonlinear optical crystal is obtained. It is also possible to use harmonics that have been converted into ultraviolet light.

In addition, the exposure apparatus 21 of the said embodiment is manufactured as follows, for example.
That is, first, at least a part of a plurality of lenses 28 or optical elements such as mirrors constituting the illumination optical system 23 and the projection optical system 25 is held by an optical element holding device such as the lens cell 29 of this embodiment, and this illumination is performed. The optical system 23 and the projection optical system 25 are incorporated in the main body of the exposure apparatus 21, and optical adjustment is performed. Next, a wafer stage 26 (including a reticle stage 24 in the case of a scan type exposure apparatus) made up of a large number of mechanical parts is attached to the main body of the exposure apparatus 21 to connect wiring. Then, a gas supply pipe for supplying gas is connected in the optical path of the exposure light, and further comprehensive adjustment (electric adjustment, operation check, etc.) is performed.

  Here, each part which comprises an optical element holding | maintenance apparatus is assembled after removing impurities, such as processing oil and a metal substance, by ultrasonic cleaning. The exposure apparatus 21 is preferably manufactured in a clean room in which the temperature, humidity, and pressure are controlled and the cleanness is adjusted.

  As the glass material in the embodiment, fluorite, synthetic quartz and the like have been described as an example. However, lithium fluoride, magnesium fluoride, strontium fluoride, lithium-calcium-aluminum-fluoride, lithium-strontium-aluminum-fluoride, and the like have been described. Crystals, fluoride glass composed of zirconium-barium-lanthanum-aluminum, quartz glass doped with fluorine, quartz glass doped with hydrogen in addition to fluorine, quartz glass containing OH groups, OH in addition to fluorine Even when improved quartz such as quartz glass containing a group is used, the optical element holding device of the embodiment can be applied.

Next, an embodiment of a device manufacturing method using the above-described exposure apparatus 21 in a lithography process will be described.
FIG. 10 is a flowchart showing a manufacturing example of a device (a semiconductor element such as an IC or LSI, a liquid crystal display element, an image pickup element (CCD or the like), a thin film magnetic head, a micromachine, or the like). As shown in FIG. 10, first, in step S101 (design step), function / performance design (for example, circuit design of a semiconductor device) of a device (microdevice) is performed, and pattern design for realizing the function is performed. Do. Subsequently, in step S102 (mask manufacturing step), a mask (such as a reticle R) on which the designed circuit pattern is formed is manufactured. On the other hand, in step S103 (substrate manufacturing step), a substrate (or a wafer W when a silicon material is used) is manufactured using a material such as silicon or a glass plate.

  Next, in step S104 (substrate processing step), using the mask and substrate prepared in steps S101 to S103, an actual circuit or the like is formed on the substrate by lithography or the like, as will be described later. Next, in step S105 (device assembly step), device assembly is performed using the substrate processed in step S104. Step S105 includes processes such as a dicing process, a bonding process, and a packaging process (chip encapsulation or the like) as necessary.

  Finally, in step S106 (inspection step), inspections such as an operation confirmation test and a durability test of the device manufactured in step S105 are performed. After these steps, the device is completed and shipped.

  FIG. 11 is a diagram showing an example of a detailed flow of step S104 of FIG. 10 in the case of a semiconductor device. In FIG. 11, in step S111 (oxidation step), the surface of the wafer W is oxidized. In step S112 (CVD step), an insulating film is formed on the surface of the wafer W. In step S113 (electrode formation step), an electrode is formed on the wafer W by vapor deposition. In step S114 (ion implantation step), ions are implanted into the wafer W. Each of the above steps S111 to S114 constitutes a pretreatment process at each stage of the wafer processing, and is selected and executed according to a necessary process at each stage.

  At each stage of the wafer process, when the above pre-process is completed, the post-process is executed as follows. In this post-processing process, first, a photosensitive agent is applied to the wafer W in step S115 (resist formation step). Subsequently, in step S116 (exposure step), the circuit pattern of the mask (reticle R) is transferred onto the wafer W by the lithography system (exposure apparatus 21) described above. Next, in step S117 (developing step), the exposed wafer W is developed, and in step S118 (etching step), the exposed members other than the portion where the resist remains are removed by etching. In step S119 (resist removal step), the resist that has become unnecessary after the etching is removed.

Multiple circuit patterns are formed on the wafer W by repeatedly performing these pre-processing and post-processing steps.
If the device manufacturing method of this embodiment described above is used, the exposure apparatus 21 is used in the exposure step (step S116), the resolution can be improved by the exposure light EL in the vacuum ultraviolet region, and the exposure amount can be controlled. It can be performed with high accuracy. Therefore, as a result, a highly integrated device having a minimum line width of about 0.1 μm can be produced with a high yield.

1 is a schematic block diagram that shows an exposure apparatus of a first embodiment. Partially broken perspective view showing the lens cell of FIG. The perspective view which shows the holding | maintenance part of FIG. 2 is an exploded perspective view of the holding unit of FIG. The fragmentary top view of the frame centering on the mounting part of FIG. FIG. 6 is a sectional view taken along line 6-6 of FIG. The top view which expands and shows the weight support mechanism of FIG. Explanatory drawing regarding the setting method of the thickness of several pairs notch spring which produces a reaction force equivalent to the case where a mounting part is supported by a pair of notch spring. The fragmentary top view of the frame centering on the mounting part of 2nd Embodiment. The flowchart of the manufacture example of a device. 11 is a detailed flowchart regarding the substrate processing of FIG. 10 in the case of a semiconductor device.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 21 ... Exposure apparatus, 25 ... Projection optical system, 27 ... Lens barrel, 28 ... Lens as optical element, 28a ... Flange part which makes a peripheral part, 29 ... Lens cell as optical element holding device, 32 ... Frame, 33 ... holding part, 34 ... mounting part, 36a to 36c ... slit, 37a, 37b ... notch spring as elastic deformation piece, 38 ... elastic deformation part, b ... length in optical axis direction of lens of notch spring, EL: exposure light, NA: neutral axis, R: reticle as a mask, h, T: thickness, wafer as a W substrate.

Claims (11)

In an optical element holding device that holds an optical element,
A frame, and a holding portion provided on the frame, the holding portion being placed on the rim of the optical element and a tangential direction of the optical element, or of the optical element A plurality of elastic members that extend in a direction intersecting the tangential direction at a predetermined angle and that are separated from each other by a predetermined distance in the radial direction of the optical element, and that connect the mounting portion so as to be displaceable in the radial direction of the optical element. An optical element holding device comprising: a deforming portion. 2. The optical device according to claim 1, wherein the elastically deforming portion includes a thin plate-like elastically deforming piece having a length substantially equal to that of the mounting portion in the optical axis direction of the optical element. Element holding device. The said elastic deformation part has a pair of elastic deformation piece provided in the one side and the other side of said mounting part regarding the said tangential direction or the said crossing direction, The Claim 1 or 2 characterized by the above-mentioned. Optical element holding device. The mounting portion is defined by a slit that penetrates the frame body in the optical axis direction of the optical element, and the elastic deformation piece is defined by a slit that penetrates the frame body in the optical axis direction of the optical element. The optical element holding device according to claim 3, wherein the optical element holding device is a plate spring. 5. The optical device according to claim 3, wherein the support point of the optical element in the mounting portion is formed on a neutral axis at which the support rigidity of the optical element by each of the elastic deformation pieces is substantially equal. Element holding device. The optical element holding device according to any one of claims 2 to 5, wherein a thickness of each of the elastic deformation pieces in the radial direction of the optical element is uniform. The pair of elastic deformation pieces on the optical element side and the pair of elastic deformation pieces on the frame body side are connected to the mounting portion at positions shifted in a tangential direction of the optical element. The optical element holding device according to any one of claims 3 to 6. In a lens barrel that holds a plurality of optical elements,
A lens barrel characterized by holding at least one of the optical elements via the optical element holding device according to any one of claims 1 to 7. In an exposure apparatus that exposes a substrate with exposure light via a plurality of optical elements,
An exposure apparatus, wherein at least one of the plurality of optical elements is held via the optical element holding device according to any one of claims 1 to 7. The exposure apparatus according to claim 9, wherein the plurality of optical elements constitute a projection optical system that projects an image of a pattern formed on a mask onto the substrate. In a device manufacturing method including a lithography process,
11. The device manufacturing method using the exposure apparatus according to claim 9 or 10 in the lithography process.

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