JP2006304480A - Multistage box actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multistage box actuator for combining a sufficient stroke and a high rigidity without use of an enlargement mechanism with a large drive loss even if piezoelectric elements are used, arbitrarily setting the minimum drive quantity smaller than the intrinsic minimum drive quantity of the piezoelectric element, easily disposed in a lens barrel since it is elongated in one direction, and saving a space of a lens driving mechanism. <P>SOLUTION: The multistage box actuator has a box frame structured so as to have a recess for disposing the first piezoelectric element in the center and a second recess oppositely opened on both sides of the recess and disposing the second piezoelectric element. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a multistage box actuator related to a lens driving mechanism of an exposure apparatus.

  In order to improve the integration degree and operation speed of solid-state elements such as LSIs, circuit patterns have been miniaturized. At present, for these pattern formations, semiconductor exposure apparatuses using a reduction projection exposure method having excellent mass productivity and resolution performance are widely used. In this method, circuit patterns on a mask, which is an original plate on which a transfer pattern is drawn, are collectively transferred to a silicon wafer on a substrate to be exposed via a projection lens. Also, an original (mask) having many different types of patterns is transferred to a substrate (silicon wafer). In order to create a highly integrated circuit, it is essential to improve not only the resolution performance but also the overlay accuracy.

  Overlay errors in a semiconductor exposure apparatus are classified into alignment errors, image distortions, and magnification errors. The alignment error is reduced by adjusting the relative position between the original (mask) and the substrate (wafer). On the other hand, the magnification error can be adjusted by moving a part of the projection optical system in the optical axis direction. When moving in the optical axis direction, it is necessary to prevent other components other than the moving direction, in particular parallel eccentricity and tilt error, from increasing.

  When an overlay error as described above occurs, a lens moving device is used for adjusting the projection magnification of the semiconductor exposure apparatus, and the overlay error is corrected by moving the lens position in the optical axis direction. Although the lens position is measured by the displacement sensor, the output value may fluctuate (drift) due to temperature fluctuations. Since this leads to a result of causing an error such as magnification and aberration, it is desirable to perform relative reference position correction. Therefore, the lens position is adjusted by providing an origin position and using that position as a reference.

  As a movable part of the lens driving device, a lens driving mechanism having a stroke longer than the original stroke of the piezoelectric element is known by an enlargement mechanism including a piezoelectric element, an elastic hinge, and a rigid link.

  Further, the following technology is disclosed for an actuator using a piezoelectric element as a drive mechanism of a general mechanical device.

  For example, Patent Document 1 discloses an excitation mechanism for canceling disturbance vibrations for an active vibration isolator for an engine mount of an automobile.

Patent Document 1 discloses a widening mechanism in which piezoelectric elements are arranged in series in order to generate more vibrations than large disturbance vibrations, thereby generating necessary vibrations.
JP-A-4-203629

  However, the above known technique has the following problems.

  In Patent Document 1, the disclosed drive mechanism uses a “bent bracket” in order to arrange the actuators in series. However, in this S-shape, the bracket is bent by an external load. As a further problem, since there is no mechanism for maintaining the posture of the metal fitting, the rigidity value is considerably lowered because the metal fitting itself moves so as to rotate.

  Further, when the actuator is considered as a piezoelectric element, this mechanism that applies a bending moment to a piezoelectric element that is weak against bending moment and shearing force is a problem.

  If an unnecessary moment is applied to the piezoelectric element, it may worst cause damage to the piezoelectric element.

  In Patent Document 1, since there is no mechanism for holding the posture of the S-shaped metal fitting itself, even when the piezoelectric element is driven, the metal fitting itself behaves so as to rotate. Result.

  In Patent Document 1, in the disclosed drive mechanism, since the piezoelectric elements are arranged in series, the stroke is increased and the actuator is configured by a plurality of actuators, so that the minimum drive amount can be miniaturized. As can be seen, since there is no mechanism for maintaining the posture of the S-shaped metal fitting itself as described above, the stroke is absorbed and the minimum drive amount cannot be reduced.

  The object of the invention according to the present application is to achieve both sufficient stroke and high rigidity without using an enlargement mechanism with a large driving loss even when a piezoelectric element is used, and more than the original minimum driving amount of the piezoelectric element. In addition, the minimum drive amount can be set arbitrarily, and because it is long in one direction, it can be easily placed in the lens barrel, and the space for the lens drive mechanism can be saved. It is to propose an actuator.

  In order to achieve the above object, a first invention according to the present application has a recess for arranging the first piezoelectric element in the center, and is opened on both sides of the side of the recess in a direction opposite to the recess. The present invention is characterized by a box-type frame having a structure in which a second recess for arranging a second piezoelectric element having each of the above is provided.

  In order to achieve the above object, according to a second invention of the present application, a second piezoelectric element is arranged on a pedestal for arranging the second piezoelectric element according to claim 1, and the second piezoelectric element is provided. The box-type frame is arranged so as to be arranged in the recesses opened in opposite directions on both sides of the box-type frame according to claim 1, and the first piezoelectric element is arranged in the central recess of the box-type frame according to claim 1. An element is arranged, and this is the first stage. Next, the box-shaped frame according to claim 1 is arranged in a recess of a second box-shaped frame which is a structure similar to the box-shaped frame according to claim 1. The third piezoelectric element is arranged in the central recess of the second box frame, and is arranged in a multistage manner so as to form a three-stage piezoelectric element and a two-stage box frame.

  In order to achieve the above object, a third invention according to the present application is characterized in that, in the lens driving unit having the structure according to claim 2, the eigenvalue of the movable part has a rigidity such that it is several hundred Hz or more. And

  In order to achieve the above object, according to a fourth aspect of the present invention, when only one of the second piezoelectric elements arranged on the pedestal is extended by a minimum driving amount among the piezoelectric elements according to claim 1, When the distance between the second piezoelectric element and the first piezoelectric element and the distance between the first piezoelectric element and the second piezoelectric element on the opposite side of the same pedestal are equal, at the tip of the first piezoelectric element, the minimum The structure is such that a drive amount that is half of the drive amount can be obtained.

  In order to achieve the above object, a fifth invention according to the present application is the same as the first piezoelectric element, the distance between the second piezoelectric element and the first piezoelectric element arranged on the pedestal according to claim 2. It features a structure that allows the minimum drive amount of the entire actuator to be set to a minimum minimum drive amount from the minimum drive amount of a single piezoelectric element by changing the distance to the second piezoelectric element on the opposite side of the pedestal. To do.

  In order to achieve the above object, according to a sixth aspect of the present application, by increasing the number of stages described in claim 2 or 4, the minimum drive amount of the entire actuator is further increased from the minimum drive amount of the single piezoelectric element. It is characterized by a structure that can be arbitrarily set to the minimum drive amount.

  In order to achieve the above object, according to a seventh aspect of the present application, in the multistage box actuator according to claim 1, between the actuator (piezoelectric element) weak to a shearing force and a bending moment and the box frame, It is characterized by a structure provided with a connector having a protective function for reducing shearing force and bending moment.

  In order to achieve the above object, according to an eighth aspect of the present invention, in the multistage box actuator according to claim 1, the bending moment and the linear elasticity applied to the piezoelectric elements arranged in the box frame are reduced. For this purpose, a leaf spring or a bellows, which is weak in the expansion / contraction direction of the piezoelectric element and strong in the direction perpendicular to the piezoelectric element, is arranged so as to cover the piezoelectric element arranged in the recess of the box-type frame. .

  In order to achieve the above object, a ninth invention according to the present application has a shape similar to that of claim 7 and covers a piezoelectric element disposed in a concave portion of a box-type frame, and is waterproof to maintain humidity in the concave portion. It is characterized by a functional lid.

  In order to achieve the above object, the tenth invention according to the present application has a long shape in one direction by arranging the box-shaped frame in multiple stages as described in claim 2, thereby making the direction more rigid. Is different (higher in the longitudinal direction than in the short direction), and in order to correct the optical performance of the exposure optical system of the exposure apparatus that transfers the pattern drawn on the original plate onto the substrate, the optical element is moved in the optical axis direction. It has a mechanism equivalent to that of a lens drive system, characterized in that it has a high degree of rigidity around the optical axis and translational direction of the lens for driving, and a low degree of rigidity around the radius and tangential axis. .

  In order to achieve the above object, the eleventh invention according to the present application facilitates deformation in the short direction of the pedestal according to claim 2 in order to make the radial rigidity according to claim 3 weaker. It has a hinge mechanism.

  In order to achieve the above object, a twelfth aspect of the present invention is characterized in that the structure according to claim 2 is turned upside down.

  According to the invention of the present application, by adopting a highly rigid box-shaped frame, connecting the piezoelectric elements in multiple stages, and supporting the box-shaped frame in parallel, by supporting in parallel with the piezoelectric elements, The drive mechanism as a whole can have high rigidity and a high eigenvalue (several hundred Hz or more).

  In addition, since the enlargement mechanism is not used, it is possible to avoid low eigenvalues due to low rigidity due to enlargement and stroke loss due to the enlargement mechanism.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to examples.

(First embodiment)
A semiconductor exposure apparatus using a lens driving unit to which the present invention is applied will be described with reference to FIGS.

  FIG. 1 shows a part of a projection optical system unit of a semiconductor exposure apparatus to which the present invention is applied. In FIG. 1, 101 is a lens barrel including a projection optical system in the semiconductor exposure apparatus of this embodiment, 102 is a main body platen that supports the lens barrel 101, 103 is a wafer coated with a photosensitive agent, and 104 is a wafer. 103 is a wafer stage that supports the wafer 103, 105 is a reticle (original) depicting a pattern to be transferred to the wafer 103, 106 is a reticle stage that holds the reticle 105, and 107 is a part of an illumination optical unit that illuminates the reticle 105 with exposure light. , 108 are located on the main body surface plate 102, and are an outer cylinder that holds the reticle stage 106, and 109 is a lens driving unit that is a part of the projection optical system. The reticle 105 is exposed by the illumination system optical unit 107, and the pattern of the reticle 105 is transferred to the wafer 103 via the projection optical system lens (inside the lens barrel 101).

  FIG. 2 shows a lens driving unit to which the present invention is applied. In FIG. 2, 201 is a lens that is a part of the projection optical system, 202 is a movable part that holds the lens and moves up and down, 203 is a multistage box-type actuator of the present invention, and 204 is a reference of the movable part 202. It is a fixed part.

  Since the shape of the multi-stage box actuator 203 of the present invention is long in one direction, it can be easily arranged in a narrow part like the fixed part 204 and can be easily approached to the movable part.

  3 and 4 are drawings that best illustrate the features of the present invention, and FIG. 3 is an overview of the multi-stage box actuator 203 of the present invention shown in FIG. FIG. 4 is a cross-sectional view of the multi-stage box actuator of FIG. Both FIG. 3 and FIG. 4 show other-stage actuators in the case of three stages. 401a and 401b are pedestals for installation on the 204 fixing portion of FIG. 2, 402a and 402b are pedestals 401a, 402c and 402d are first-stage piezoelectric elements arranged on the pedestal 401b, and 403a is a piezoelectric element. First-stage box frame supported by 402a and 402b, similarly 403b is a first-stage box frame supported by piezoelectric elements 402c and 402d, and 404a is a second-stage box frame disposed on the box frame 403a. Similarly, 404b is a second-stage piezoelectric element disposed on the box frame 403b, 405 is a piezoelectric element 404a, a box frame supported by the piezoelectric element 404b, and 406 is a box frame 405. Reference numeral 407 denotes a third-stage piezoelectric element disposed on the coupling member for fixing the piezoelectric element 406 and the movable portion 202 shown in FIG.

  Here, the structure of Patent Document 1 and the present invention will be compared.

  Patent Document 1 has a mechanism as shown in FIG. This is composed of an upper piezoelectric element 92, a lower piezoelectric element 92, and a metal fitting 93 for connecting the upper and lower piezoelectric elements. In the case of one-to-one top and bottom, if the piezoelectric elements are not supported at the center, the posture of the metal fitting 93 cannot be maintained, and it rotates as indicated by the chain line in FIG. Will be loaded.

  On the other hand, in the present invention, as shown in FIG. 5B showing a mechanism diagram of the minimum unit (claim 1) of the multi-stage box actuator, the box frame 403a for coupling the piezoelectric elements is provided as a piezoelectric element. Since it is supported by 402a and 402b, the posture of the box-type frame can be maintained, and a bending moment is not applied to each piezoelectric element. FIG. 5C is an overall mechanism diagram of the multistage box-type actuator.

  As shown in FIG. 5C, a portion surrounded by a two-dot chain line is a mechanism diagram of the minimum unit shown in FIG. 5B. If this is considered as one actuator, FIG. Can be replaced as shown in FIG. This is equivalent to FIG. 5B, that is, it is understood that the mechanism is well balanced as a whole.

  Next, the operation of the multistage box actuator 203 will be described.

  In the above configuration, the first-stage piezoelectric elements 402a, 402b, 402c, and 402d of the multi-stage box-type actuator 203 arranged in the fixed portion 204 of FIG. 404b expands by s2, the third-stage piezoelectric element 406 expands by s3, and S (= s1 + s2 + s3) expands in the entire multistage box actuator.

  Thereby, when the all-stage box actuator is extended, the lens 201 and the movable portion 202 can be extended by the stroke S in the optical axis direction.

  In the case of these three stages, if a piezoelectric element of the same size is used, a stroke that is three times as high as that of one piezoelectric element is obtained.

Further, when one multistage box actuator is extended, the lens 201 and the movable portion 202 are D, where the support section diameter of the multistage box actuator is D.
Can only tilt.

  Next, the minimum drive amount of the multistage box actuator will be described.

  6A and 6B show only the first stage in the mechanism diagram of FIG.

  When the minimum driving amount of each piezoelectric element is Δs and only the piezoelectric element 402a is driven by Δs, the box-shaped frame tilts with the connection portion between the piezoelectric element 402b and the box-shaped frame 403a as a fulcrum.

In addition, when the distance between the piezoelectric element 404a and the piezoelectric element 402a and the distance between the piezoelectric element 404a and the piezoelectric element 402b are equal, the minimum driving amount in the piezoelectric element 404a is
become. Further, FIG. 5C shows a mechanism representing the whole of FIG.

When only the piezoelectric element 402a is driven by Δs, the minimum driving amount of the piezoelectric element 404a is reduced.
Furthermore, the minimum drive amount at the coupling member at the final output end is
become.

(Second embodiment)
In the first embodiment, the minimum drive amount has been described.

  Next, it is shown that the minimum drive amount can be set by changing the interval between the piezoelectric elements.

In this second embodiment, the final output end is
The case where it makes is explained.

  FIGS. 7A and 7B show that the piezoelectric element 404a of FIG. 5A has a distance of “1: 4” between “piezoelectric element 404a and piezoelectric element 402b” and “piezoelectric element 404a and piezoelectric element 402a”. FIG.

As in the second embodiment, when only the piezoelectric element 402a is driven by Δs, the minimum driving amount of the piezoelectric element 404a is reduced.
become.

  Further, FIG. 6C shows a mechanism representing the whole.

As in the third embodiment, when only the piezoelectric element 402a is driven by Δs, the minimum driving amount of the piezoelectric element 404a is reduced.
Furthermore, the minimum drive amount at the coupling member at the final output end is
It becomes.

  The minimum drive amount can be arbitrarily set by arbitrarily setting the ratio of the intervals between “piezoelectric elements 404a and 402b” and “piezoelectric elements 404a and 402a” and increasing the number of stages.

(Third embodiment)
FIG. 8 shows a mechanism incorporating a tanning mechanism for further reducing the shearing force and bending moment applied to the piezoelectric element in the multistage box actuator due to the driving of the piezoelectric element itself and the mass of the movable part. As a specific example, a mechanism in which an elastic hinge is provided between the piezoelectric element and the box frame is shown.

  Further, when providing elastic hinges at both ends of the piezoelectric element, it is necessary to further provide a guide for driving the box frame in the vertical direction.

  However, this elastic hinge also causes drive loss, so it is better not to provide it as much as possible.

  In order to solve this problem, (1) the mass of the movable part is reduced so that the load due to the mass of the movable part is not applied to the piezoelectric element, and similarly (2) the load is not applied to the piezoelectric element. Furthermore, the drive amount of each piezoelectric element is made appropriate with respect to the drive amount required at the final end of the multi-stage box actuator, and each box frame is not inclined extremely. (1), (2 (3) The piezoelectric element itself may have a structure that can withstand shearing force and bending moment.

(Fourth embodiment)
FIG. 9 shows a mechanism incorporating a protective mechanism for reducing the shearing force and bending moment applied to the piezoelectric element for the same purpose as the third embodiment.

  By placing a leaf spring or bellows, etc. that is weak in the expansion and contraction direction of the piezoelectric element and strong in the direction perpendicular to it so as to cover the piezoelectric element arranged in the recess of the box frame, it is arranged in the box frame. This reduces the bending moment and shear force applied to the piezoelectric element.

  Furthermore, it is also conceivable to use it together with the third embodiment.

(Fifth embodiment)
By covering the piezoelectric element disposed in the recess of the box-shaped frame with a shape similar to that of FIG. 9, the recess is sealed, and a waterproof function is provided to keep the humidity in the recess.

  Furthermore, it can be considered to be used together with the fourth embodiment.

(Sixth embodiment)
FIG. 10 shows a multi-stage box-type actuator in which walls are provided at both ends to strengthen the box-type frames 404a, 404b, and 405 to have higher rigidity.

(Seventh embodiment)
In the lens driving unit of FIG. 2, ideally, the rigidity of the driving mechanism is such that the translation of three axes, the rotation around the optical axis is hard, and the rotation around the radius and the tangent is weak among six degrees of freedom. Originally, according to the present invention, the rotation around the tangent line is weak due to the structure. However, in order to further weaken the pedestal 401a, 401b, which is a lower part of the multi-stage box actuator, as shown in FIG. This mechanism is provided with an elastic hinge to facilitate displacement of the actuator in the short direction.

1 is an overall view for explaining a projection optical system unit of a semiconductor exposure apparatus in a first embodiment of the present invention; 1 is an overall view illustrating a lens driving unit according to a first embodiment of the present invention. FIG. 1 is an external view illustrating a multistage box actuator according to a first embodiment of the present invention. Sectional drawing explaining the multistage box-type actuator in 1st Example of this invention Operation explanatory diagram for explaining the minimum driving amount of the multistage box actuator in the first embodiment of the present invention Operation explanatory diagram for explaining the minimum driving amount of the multistage box actuator in the first embodiment of the present invention Operation explanatory diagram for explaining that the minimum drive amount of the multi-stage box actuator in the second embodiment of the present invention can be set by arbitrarily changing the arrangement interval of the piezoelectric elements. FIG. 9 is a mechanism diagram for explaining a mechanism incorporated in order to reduce shearing force and bending moment applied to the piezoelectric element of the multistage box-type actuator in the third embodiment of the present invention. Mechanism diagram for explaining the mechanism incorporated for protection from the shearing force and bending moment applied to the piezoelectric element of the multi-stage box actuator in the fourth and fifth embodiments of the present invention, and for waterproofing. External view of multi-stage box actuator with reinforced box frame in the fifth embodiment of the present invention External view for explaining a pedestal provided with an elastic hinge for lowering the rigidity in the short direction of the multi-stage box actuator in the third embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Lens tube 102 Main body surface plate 103 Wafer 104 Wafer stage 105 Reticle (original)
106 reticle stage 107 part of illumination system optical unit 108 outer cylinder 109 lens drive unit 201 lens 202 movable part 203 multistage box actuator 204 fixed part 401a pedestal 401b pedestal 402a first stage piezoelectric element a
402b First stage piezoelectric element b
402c First stage piezoelectric element c
402d First stage piezoelectric element d
403a First stage box frame a
403'a Closed box frame a at both ends of the first stage
403b First stage box frame b
404a Second stage piezoelectric element a
404b Second stage piezoelectric element b
405 Second stage box-shaped frame 406 Third stage piezoelectric element 407 Connecting member 402.4a Bellows 402.4b of first stage piezoelectric element a Bellows 404.4a of first stage piezoelectric element b Second stage piezoelectric Bellows 406.4 of the element a Bellows 402.5a of the third-stage piezoelectric element 40 Twist mechanism 402.5b of the first-stage piezoelectric element a Twist mechanism 404.5a of the first-stage piezoelectric element b The wetting mechanism of the piezoelectric element a 406.5 The wetting mechanism of the third-stage piezoelectric element

Claims (12)

  A concave portion for arranging the first piezoelectric element in the center, and a second concave portion for arranging a second piezoelectric element having an opening opposite to the concave portion on both sides of the side portion of the concave portion. A multi-stage box-type actuator characterized by a box-type frame with a structure provided respectively.   A second piezoelectric element is arranged on a pedestal for arranging the second piezoelectric element according to claim 1, and the second piezoelectric element is opened in opposite directions on both sides of the box-shaped frame according to claim 1. A box-shaped frame is disposed so as to be disposed in the recessed portion, and a first piezoelectric element is disposed in the central recessed portion of the box-shaped frame according to claim 1, which is the first stage, and then, according to claim 1. The box-shaped frame according to claim 1 is arranged in a concave portion of a second box-shaped frame which is a structure having a similar shape to the box-shaped frame described above, and a third concave portion is arranged in the central concave portion of the second box-shaped frame. 2. The multistage box actuator according to claim 1, wherein piezoelectric elements are arranged and arranged in a multistage manner so as to form a three-stage piezoelectric element and a two-stage box frame.   3. A multistage box actuator, wherein the lens drive unit having the structure according to claim 2 has a rigidity such that the eigenvalue of the movable part is several hundred Hz or more.   If only one of the second piezoelectric elements arranged on the pedestal is extended by a minimum driving amount among the piezoelectric elements according to claim 1, the distance between the second piezoelectric element and the first piezoelectric element, A multi-stage system characterized in that when the distance between one piezoelectric element and the second piezoelectric element on the opposite side of the pedestal is equal, the tip of the first piezoelectric element can obtain a drive amount that is half the minimum drive amount. Box actuator.   The distance between the second piezoelectric element arranged on the pedestal according to claim 2 and the first piezoelectric element and the distance between the first piezoelectric element and the second piezoelectric element on the opposite side of the pedestal are changed. Therefore, the minimum drive amount of the entire actuator can be arbitrarily set to a minute minimum drive amount from the minimum drive amount of the piezoelectric element alone, and the multistage box-type actuator characterized by its structure.   5. A multi-stage box type characterized in that by increasing the number of stages according to claim 2 or 4, the minimum drive amount of the entire actuator can be arbitrarily set to a high and minimum drive amount from the minimum drive amount of a single piezoelectric element. Actuator.   In the multistage box actuator according to claim 1, in order to reduce bending moment and linear elasticity applied to the piezoelectric element disposed in the box frame, between the actuator (piezoelectric element) and the box frame, A multi-stage box actuator characterized by a structure with a connector with a protective function to reduce shearing force and bending moment.   2. The multistage box actuator according to claim 1, wherein the piezoelectric element is weak in the expansion / contraction direction and is perpendicular to the piezoelectric element in order to reduce bending moment and linear elasticity applied to the piezoelectric element disposed in the box frame. Multi-stage box actuator characterized by a strong guide mechanism.   A multi-stage box having a shape similar to that of claim 7 and covering a piezoelectric element disposed in a recess of a box-shaped frame and having a lid having a waterproof function for maintaining humidity in the recess. Type actuator.   An exposure apparatus for transferring a pattern drawn on an original plate having a shape that is long in one direction and thereby having different rigidity depending on the direction by arranging box-shaped frames in multiple stages as described in claim 2. In order to correct the optical performance of the exposure optical system, the optical element is driven in the optical axis direction, and the lens translation direction and the rigidity around the optical axis are strong, and the rigidity around the radius and tangential axis is weak. A multistage box actuator characterized by having a mechanism equivalent to the lens drive system.   A multistage box-type actuator comprising a pedestal according to claim 2 having a hinge mechanism for facilitating deformation in a short direction in order to make the radial rigidity according to claim 9 weaker.   A multistage box-type actuator characterized in that the structure according to claim 2 is turned upside down.