JP2006019510A - Aligner and fabrication process of microdevice - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aligner capable of removing unevenness in light intensity distribution of reflection light beam caused by the structure of a condenser mirror at a light source section where extreme UV light is reflected. <P>SOLUTION: The aligner comprising a light source section 2 having a light source 20 emitting extreme UV light, and a condenser mirror 22 for reflecting and condensing extreme UV light emitted from the light source and exposing a mask pattern onto a photosesitive wafer W by illuminating a mask M with extreme UV light being emitted from the light source section is further provided with means 28-36 for removing uneven light intensity distribution of reflection light caused by the structure of a condenser mirror 22. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an exposure apparatus for manufacturing a microdevice such as a semiconductor element, a liquid crystal display element, and a thin film magnetic head in a lithography process, and a method of manufacturing a microdevice using the exposure apparatus.

  Currently, in the manufacture of semiconductor integrated circuits, a photolithography technique using visible light or ultraviolet light is used to transfer a very fine pattern formed on a mask onto a photosensitive substrate. In the manufacturing process using this photolithography technique, projection exposure is performed by projecting an original pattern formed on a mask onto a photosensitive substrate coated with a photosensitive agent such as a photoresist via a projection optical system. The device is used.

  In recent years, in order to realize high integration and high density of a semiconductor integrated circuit, it is necessary to further reduce the line width of the circuit or further refine the pattern. Therefore, improvement in resolution is required in the projection exposure apparatus. In order to increase the resolution in the projection exposure apparatus, mercury lamps (365 nm), KrF excimer lasers (248 nm), ArF excimer lasers (193 nm), etc. have been put to practical use as the exposure light source wavelength so far. Further, the wavelength has been further shortened, and the use of light having a wavelength shorter than 157 nm (for example, EUV light) as an exposure light source has been studied (see Patent Document 1).

JP 11-31638 A

  A light source unit of an exposure apparatus that uses EUV light as an exposure light source includes an extreme ultraviolet light (EUV light) generation unit, and a condensing mirror for reflecting and condensing the EUV light emitted from the EUV light generation unit. It is configured. As this condensing mirror, an oblique incidence mirror that condenses EUV light using total reflection, or a multilayer mirror that reflects EUV light using a multilayer film is used. In general, when a discharge generation plasma light source is used as a light source, an oblique incidence mirror is used in order to avoid interference with a peripheral portion of the discharge light source unit. Further, when a laser-produced plasma light source is used as the light source, since a solid angle for capturing EUV light can be increased, a multilayer mirror having a spherical reflection surface or a spheroidal shape is generally used.

  When an oblique incidence mirror is used, a plurality of oblique incidence mirrors sharing the optical axis are configured in a nested manner in order to maximize the capture solid angle. In the case of using a multilayer mirror, it may be configured as a set of partial mirrors having the same curved surface (for example, a spheroidal surface) because it is difficult to manufacture a large-diameter mirror integrally. Here, in the condensing mirror constituted by the oblique incidence mirror, unevenness (non-uniformity) in the light intensity distribution occurs in the light intensity distribution of the reflected light beam due to the shadow of the mirror configured in a nested manner. Further, in a multilayer mirror configured as a set of partial mirrors, unevenness (non-uniformity) in the light intensity distribution occurs in the light intensity distribution of the reflected light flux due to shadows caused by non-reflective portions between the partial mirrors. When such a shadow portion is projected onto the arc-shaped element mirror of the incident-side fly-eye mirror, the fly-eye mirror is insufficiently uniform, and the light intensity distribution on the reticle is non-uniform.

  Moreover, since the condensing mirror is the mirror closest to the plasma, the optical characteristics of the mirror due to the plasma are severely degraded. For this reason, it is necessary to periodically replace the condenser mirror, but an oblique incidence mirror in which a plurality of oblique incidence mirrors are arranged in a nested manner is difficult to manufacture, and has the same reflection characteristics (for example, reflected light intensity distribution). It is difficult to make a mirror. Therefore, it is not always possible to supply the illumination optical system with a light beam having the same light intensity distribution as before the replacement when the condenser mirror is replaced. This situation is the same for a multilayer mirror which is an assembly of partial mirrors.

  An object of the present invention is to provide an exposure apparatus capable of removing non-uniformity in the light intensity distribution of the reflected light beam caused by the structure of the collecting mirror caused by the reflection of extreme ultraviolet light by the collecting mirror of the light source unit, It is to provide a method of manufacturing a micro device using an exposure apparatus.

  The exposure apparatus according to claim 1 includes a light source unit including a light source that generates extreme ultraviolet light and a condenser that reflects and collects the extreme ultraviolet light emitted from the light source, and is emitted from the light source unit. In an exposure apparatus that illuminates a mask using extreme ultraviolet light as illumination light and exposes the pattern of the mask onto a photosensitive substrate, the light intensity distribution of a non-uniform reflected light beam generated due to the structure of the condenser mirror It has the removal means which removes.

  The exposure apparatus according to claim 2 is characterized in that the removing means removes a non-uniform light intensity distribution of a reflected light beam caused by a shadow by a non-reflecting portion of the condenser mirror.

  According to the exposure apparatus of claim 1 and claim 2, the light intensity distribution of the non-uniform reflected light beam generated by the removing means due to the structure of the condenser mirror, for example, the non-reflective portion of the condenser mirror In order to remove the uneven light intensity distribution of the reflected light beam caused by the shadow caused by the above, the light intensity distribution of the reflected light beam can be made uniform or substantially uniform.

  The exposure apparatus according to claim 3, wherein the removing means irradiates the extreme ultraviolet light onto the photosensitive substrate while the condenser mirror is the center of a light beam emitted from the condenser mirror. It is characterized by moving in the direction.

  The exposure apparatus according to claim 4, wherein the removing means irradiates the extreme ultraviolet light onto the photosensitive substrate, and the converging mirror is a reference axis that is a center of a light beam emitted from the condensing mirror. It is characterized by being moved in a direction perpendicular to.

  The exposure apparatus according to claim 5, wherein the removing means irradiates the extreme ultraviolet light onto the photosensitive substrate and the focusing mirror is a reference axis that is a center of a light beam emitted from the focusing mirror. It is made to incline with respect to.

  The exposure apparatus according to claim 6 is a reference axis which is a center of a light beam emitted from the condenser mirror while the removing means irradiates the extreme ultraviolet light onto the photosensitive substrate. It is characterized by rotating around.

  According to the exposure apparatus according to any one of claims 3 to 6, during the irradiation of the extreme ultraviolet light onto the photosensitive substrate, the condensing mirror is moved in the reference axis direction, and the condensing mirror is perpendicular to the reference axis. The light intensity distribution of the non-uniform reflected light beam generated due to the structure of the collector mirror by tilting the collector mirror with respect to the reference axis and rotating the collector mirror around the reference axis And the light intensity distribution of the reflected light beam can be made uniform or substantially uniform.

  The exposure apparatus according to claim 7, wherein the removing unit irradiates the extreme ultraviolet light onto the photosensitive substrate, and the light source is directed toward a reference axis that is a center of a light beam emitted from the condenser mirror. It is made to move.

  The exposure apparatus according to claim 8, wherein the light source is perpendicular to a reference axis that is a center of a light beam emitted from the condenser mirror while the removing unit irradiates the extreme ultraviolet light onto the photosensitive substrate. It is characterized by moving in any direction.

  According to the exposure apparatus of claim 7 and claim 8, during irradiation of extreme ultraviolet light onto the photosensitive substrate, the light source is moved in the direction of the reference axis, and the condenser mirror is moved in the direction perpendicular to the reference axis. By doing so, it is possible to remove the light intensity distribution of the uneven reflected light beam generated due to the structure of the condenser mirror, and to make the light intensity distribution of the reflected light beam uniform or substantially uniform.

  The exposure apparatus according to claim 9, wherein the condenser mirror includes a plurality of reflecting members, and the at least one posture of the plurality of reflecting members is set during irradiation of the extreme ultraviolet light onto the photosensitive substrate. A reflection member driving means for changing is provided.

  According to the exposure apparatus of the ninth aspect, the light intensity distribution of the uneven reflected light flux generated due to the structure of the condenser mirror is removed by changing at least one posture of the plurality of reflecting members. The light intensity distribution of the reflected light beam can be made uniform or substantially uniform.

  The exposure apparatus according to claim 10, wherein the removing means irradiates the extreme ultraviolet light onto the photosensitive substrate, and the condenser mirror attitude changing means for changing the attitude of the condenser mirror, and the light source And a light source position changing means for changing the position.

  The exposure apparatus according to claim 11, wherein the condenser mirror posture changing means irradiates the extreme ultraviolet light onto the photosensitive substrate and the condenser mirror is centered on a light beam emitted from the condenser mirror. A reference axis direction, a direction in which the condenser mirror is perpendicular to the reference axis, a direction in which the condenser mirror is inclined with respect to the reference axis, and a direction in which the condenser mirror is rotated around the reference axis. The light source position changing means moves the light source in at least one of the reference axis direction and the direction perpendicular to the reference axis while the extreme ultraviolet light is irradiated on the photosensitive substrate. It is characterized by making it.

  According to the exposure apparatus of the tenth and eleventh aspects, the position of the light collecting mirror is changed and the position of the light source is changed during irradiation of extreme ultraviolet light onto the photosensitive substrate. The light intensity distribution of the non-uniform reflected light beam generated due to this structure can be removed, and the light intensity distribution of the reflected light beam can be made uniform or substantially uniform.

  The exposure apparatus according to claim 12, wherein the condensing mirror has a plurality of reflecting members, and the at least one posture of the plurality of reflecting members is set during irradiation of the extreme ultraviolet light onto the photosensitive substrate. A reflection member driving means for changing is provided.

  According to the exposure apparatus of the twelfth aspect, by changing the posture of at least one of the plurality of reflecting members, the light intensity distribution of the uneven reflected light flux generated due to the structure of the condenser mirror is removed. The light intensity distribution of the reflected light beam can be made uniform or substantially uniform.

  A microdevice manufacturing method according to a thirteenth aspect is a microdevice manufacturing method using the exposure apparatus according to any one of the first to twelfth aspects, wherein the mask pattern is transferred to the photosensitive device. An exposure step of exposing the photosensitive substrate, and a development step of developing the photosensitive substrate exposed by the exposure step.

  According to the method for manufacturing a microdevice according to claim 13, since the exposure is performed using the exposure apparatus according to any one of claims 1 to 12, the microdevice is generated due to the structure of the condenser mirror. The mask can be illuminated by the light beam from which the light intensity distribution of the non-uniform reflected light beam is removed, and a fine pattern formed on the mask can be satisfactorily exposed on the photosensitive substrate with high resolution. Here, the removing means of the present invention is not limited to removing the non-uniform light intensity distribution, but also includes a means for correcting the non-uniform light intensity distribution or a means for reducing the non-uniform light intensity. .

  According to the exposure apparatus of the present invention, the light intensity distribution of the non-uniform reflected light beam generated due to the structure of the condenser mirror by the removing means, for example, caused by the shadow by the non-reflective portion of the condenser mirror Since the non-uniform light intensity distribution of the reflected light beam is removed, the light intensity distribution of the reflected light beam can be made uniform.

  Also, according to the microdevice manufacturing method of the present invention, since the exposure is performed using the exposure apparatus of the present invention, the light intensity distribution of the uneven reflected light flux generated due to the structure of the condenser mirror is removed. The mask can be illuminated by the light flux, and a fine pattern formed on the mask can be satisfactorily exposed on the photosensitive substrate with high resolution.

  A projection exposure apparatus according to a first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a projection exposure apparatus according to this embodiment. As shown in FIG. 1, the projection exposure apparatus includes a light source device (light source unit) 2 that emits EUV (extreme ultra violet) light having a wavelength of about 5 to 40 nm. As shown in FIG. 2, the light source apparatus 2 includes a discharge generation plasma light source 20 and a condensing mirror 22 including an oblique incidence mirror that reflects and condenses EUV light emitted from the discharge generation plasma light source 20. Yes. The condensing mirror 22 is configured by nesting a plurality of oblique incidence mirrors that share the optical axis in order to make the capture solid angle as large as possible.

  Further, the light source device 2 includes a control unit 24 that controls the entire light source device. The control unit 24 moves the light source control unit 26 that controls the discharge generation plasma light source 20 and the movement of the condensing mirror 22 in the direction of the reference axis X (the reference axis X that is the center of the light beam emitted from the condensing mirror 22). A first condensing mirror drive unit 28 to perform, a second condensing mirror drive unit 30 to move the condensing mirror 22 in a direction perpendicular to the reference axis X, and a third to tilt the condensing mirror 22 with respect to the reference axis X. A condenser mirror drive unit 32 is connected. Further, a first light source drive unit 34 that moves the discharge-generated plasma light source 20 in the direction of the reference axis X and a second light source drive unit 36 that moves in the direction perpendicular to the reference axis X of the discharge-generated plasma light source 20 are connected. Yes. In addition, the 1st condensing mirror drive part 28, the 2nd condensing mirror drive part 30, the 3rd condensing mirror drive part 32, the 1st light source drive part 34, and the 2nd light source drive part 36 are a piezoelectric element, a motor, etc. The condensing mirror 22 and the discharge generation plasma light source 20 are driven. In FIG. 2, the arrows described above the first condenser mirror driving unit 28, the second condenser mirror driving unit 30, and the third condenser mirror driving unit 32 indicate the moving direction of the condenser mirror 22. The arrows shown below the first light source driving unit 34 and the second light source driving unit 36 indicate the moving direction of the discharge generation plasma light source 20.

  The luminous flux emitted from the discharge generation plasma light source 20 is condensed by the condenser mirror 22, emitted from the light source device 2, and enters the collimator mirror 4 configured by a spherical mirror. The EUV light incident on the collimator mirror 4 is reflected and condensed by the condensing action (collimating action) of the collimator mirror 4 to become a substantially parallel light beam. On the reflection surface of the collimator mirror 4, a multilayer film in which a plurality of substances among molybdenum, ruthenium, rhodium, silicon, and silicon oxide are deposited is formed. The EUV light is guided to a reflective fly's eye optical system (a reflective member that guides to the mask M) that constitutes the optical integrator in a substantially parallel light beam state, and is incident on the reflective fly eye optical system that constitutes the reflective fly's eye optical system. Incident on the eye mirror 6.

  The incident-side reflection type fly-eye mirror 6 includes a plurality of reflective elements that are constituted by spherical mirrors and are arranged in parallel, and a mask (reticle) M or a photosensitive substrate (wafer) as an irradiation surface or an exposure surface described later. ) It is arranged at a position optically conjugate with W or in the vicinity thereof. The EUV light incident on the incident-side reflective fly-eye mirror 6 is reflected by the incident-side reflective fly-eye mirror 6 and enters the other exit-side reflective fly-eye mirror 8 that constitutes the reflective fly-eye optical system. The exit-side reflection fly-eye mirror 8 includes a plurality of reflecting elements that are configured by spherical mirrors and arranged in parallel, and is disposed on or near the pupil plane of the illumination optical system.

  3 is a front view showing the incident-side reflection type fly-eye mirror 6, and FIG. The element optical systems 6a of the incident-side reflection type fly-eye mirror 6 and the element optical systems 8a of the emission-side reflection type fly-eye mirror 8 are arranged in a one-to-one correspondence, and have the same focal length. have. The light beam incident on the incident-side reflection type fly-eye mirror 6 is divided into wavefronts by the respective elemental optical systems 6 a of the incident-side reflection type fly-eye mirror 6. A large number of light beams that have been wavefront-divided by the incident-side reflection type fly-eye mirror 6 are incident on the exit-side reflection type fly-eye mirror 8, and each element optical system 8a of the emission-side reflection type fly-eye mirror 8 is wavefront-divided. Each individual luminous flux is received one by one. Here, since the element-side optical system 6a of the incident-side reflection type fly-eye mirror 6 and the exposed surface on the mask M are arranged in a conjugate manner, the emission-side reflection type fly-eye mirror 8 is a surface light source in Koehler illumination. It becomes.

  The EUV light reflected by the exit-side reflective fly-eye mirror 8 is incident on one incident-side reflective condenser mirror 10 constituting the condenser optical system. The incident side reflection type condenser mirror 10 is constituted by a spherical mirror. The EUV light incident on the incident-side reflective condenser mirror 10 is reflected by the incident-side reflective condenser mirror 10 and enters the other exit-side reflective condenser mirror 12 that constitutes the reflective condenser optical system. The exit side reflection type condenser mirror 12 is constituted by a spherical mirror. Here, the incident-side condenser mirror 10 and the emission-side condenser mirror 12 are arranged so that the vertical distance therebetween is shorter than the distance between the object images of the mask M and the wafer (photosensitive substrate) W. An exit side condenser mirror 12 is arranged.

  The EUV light incident on the condenser optical system is sequentially reflected by the incident-side reflective condenser mirror 10 and the outgoing-side reflective condenser mirror 12 to form a predetermined circuit pattern, and the reflective mask placed on the mask stage MS. Uniformly illuminate over M. The EUV light reflected by the reflective mask M is placed on the wafer stage WS and applied as a photosensitive substrate coated with a resist via a reflective projection optical system PL including a plurality of imaging reflecting members (not shown). A pattern image formed on the mask M on the wafer W is projected and exposed.

  This projection exposure apparatus includes a shutter S in an optical path between the light source device 2 and a collimator mirror 4 that is a reflection member disposed closest to the light source device 2 among the plurality of reflection members. Accordingly, the shutter S can prevent the dust falling from the light source electrode of the light source device 2 and the target supply nozzle from adhering to the collimator mirror 4.

  In addition, the projection exposure apparatus includes a wavelength selection filter F in an optical path between the shutter S and a collimator mirror 4 that is a reflection member disposed closest to the light source device 2 among the plurality of reflection members. Among the light emitted from the light source device 2 by the wavelength selection filter F, light having a longer wavelength and light having a shorter wavelength than light necessary for exposure are blocked and only light necessary for exposure is transmitted.

  As shown in FIG. 5, in this projection exposure apparatus, the position of the shadow of the oblique incidence mirror after passing through the aperture AP because the condensing magnification is changed by moving the condensing mirror 22 in the reference axis X direction. Changes. FIG. 6 shows the light intensity distribution of the light beam after passing through the aperture when the condenser mirror 22 is at the first position “position A”, and “position B” where the condenser mirror 22 is the second position. 2 shows the light intensity distribution of the light beam after passing through the aperture.

  Accordingly, the control unit 24 causes the first condenser mirror to irradiate the wafer W with the EUV light emitted from the discharge generation plasma light source 20 under the control of the light source control unit 26 based on the control signal from the control unit 24. When a control signal is output to the drive unit 28 and exposure is performed while changing the position of the condensing mirror 22 in the reference axis X direction, the intensity at which one point on the wafer W is exposed is the light at these various condensing positions. Since the intensity distributions are superposed, the steep change in the light intensity distribution incident on the incident-side reflection type fly-eye mirror 6 constituting the fly-eye optical system is alleviated, and the shadow portion of the oblique incidence mirror is smoothed and uniform. Exposure can be performed. “During irradiation” described here means, for example, in the case of a light source that emits pulsed light, during a series of pulse irradiations, and not during one pulse irradiation.

The amplitude for moving the condenser mirror 22 is about several μm to several mm, although it depends on the magnification of the condenser mirror 22. The speed of vibration is not limited as long as it can move by at least a half cycle or an integral multiple of a half cycle within a time when exposure light is irradiated to one point on the wafer W. Therefore,
w: exposure width in the scan direction on the wafer [mm]
v: Wafer stage scan speed [mm / sec]
When
Period = 2w / v [sec]
Frequency = v / 2w [Hz]
It becomes.

  For example, when the exposure width in the scanning direction on the wafer W is 2 mm and the scanning speed of the wafer stage WS is 100 mm / sec, the time during which one point on the wafer W is receiving the exposure light is 2/100 = 20 msec. . Since this is a 1/2 cycle, it may be a cycle shorter than at least 40 msec, and the condenser mirror 22 may be vibrated at a frequency of 25 Hz or more in terms of frequency. In addition, when sufficient exposure amount can be made uniform in a shorter cycle than this, the condensing mirror 22 may be vibrated at a frequency lower than the above frequency. Note that the position of the opening may be changed in the direction of the reference axis, or the opening diameter of the opening may be changed in conjunction with a change in the position of the oblique incidence mirror. The frequency of vibration may be constant or may be changed randomly. Moreover, you may give a correlation with the repetition frequency of a light source, and a vibration frequency. For example, when the repetition frequency is changed, the vibration frequency may be changed in conjunction therewith. Alternatively, the relationship between the vibration frequency and the repetition frequency may be an integer multiple relationship, or may be intentionally excluded from the integer multiple relationship.

  In the first embodiment, a discharge generation plasma light source is used as a plasma light source and a condensing mirror composed of an oblique incidence mirror is used. However, the present invention is not limited to this, and a laser generation plasma light source is used as a plasma light source. A multilayer mirror composed of a plurality of split mirrors may be used.

  In the first embodiment described above, the condensing mirror 22 is moved (vibrated) in the reference axis direction. However, the condensing mirror 22 is moved (vibrated) in a direction perpendicular to the reference axis X. It may be. In this case, while the EUV light emitted from the discharge generation plasma light source 20 is irradiated onto the wafer W, the control unit 24 of the light source device 2 outputs a control signal to the second condenser mirror driving unit 30 to collect the light. Exposure is performed while changing the position of the mirror 22 in the direction perpendicular to the reference axis X.

  Further, the condenser mirror 22 may be inclined with respect to the reference axis X. In this case, while the EUV light emitted from the discharge generation plasma light source 20 is irradiated onto the wafer W, the control unit 24 of the light source device 2 outputs a control signal to the third condenser mirror driving unit 32 to collect the light. Exposure is performed while changing the inclination of the mirror 22 with respect to the reference axis X. Since the shape of the condensed light flux on the downstream side after the condensing changes, the light intensity of the EUV light in the shadow portion of the oblique incidence mirror may be smoothed using this.

  In the first embodiment described above, the position of the condensing mirror 22 is changed, but the discharge-generating plasma light source 20 is moved (vibrated) in the reference axis X direction or in a direction perpendicular to the reference axis X. Even if it makes it, the same effect can be acquired. In this case, a control signal is output to the first light source driving unit 34 by the control unit 24 of the light source device 2 while irradiating the wafer W with the EUV light emitted from the discharge generating plasma light source 20, and the discharge generating plasma light source Exposure is performed while changing the position of the 20 reference axis X directions. Alternatively, while the EUV light emitted from the discharge generation plasma light source 20 is irradiated onto the wafer W, the control unit 24 of the light source device 2 outputs a control signal to the second light source drive unit 36, so that the reference of the discharge generation plasma light source 20 is obtained. Exposure is performed while changing the position in the direction perpendicular to the axis X.

  The movement of the condenser mirror 22 in the direction of the reference axis X, the movement of the condenser mirror 22 in the direction perpendicular to the reference axis X, the inclination of the condenser mirror 22 with respect to the reference axis X, and the reference axis of the condenser mirror 22 The rotation around X, further the movement of the discharge generated plasma light source 20 in the direction of the reference axis X and the movement of the discharge generated plasma light source 20 in the direction perpendicular to the reference axis X are preferably performed in combination as appropriate. By removing the unevenness of the light intensity of the reflected light caused by the structure of the condenser mirror in such a combination, it is possible to effectively realize the uniform light quantity of the exposure light on the photosensitive substrate. it can.

  Next, a projection exposure apparatus according to a second embodiment of the present invention will be described with reference to the drawings. FIG. 7 is a diagram showing a schematic configuration of the light source device 200 of the projection exposure apparatus according to this embodiment. In the description of the second embodiment, a detailed description of the same configuration as that of the projection exposure apparatus according to the first embodiment is omitted, and the projection exposure apparatus according to the first embodiment is omitted. The same components will be described using the same reference numerals.

  The projection exposure apparatus includes a light source device 200 in place of the light source device 2 of the projection exposure apparatus according to the first embodiment. In the light source device 200, the light source device 2 according to the first embodiment further includes a fourth light collecting mirror driving unit 38 that rotates the light collecting mirror 22 around the reference axis X. Here, the fourth condenser mirror drive unit 38 includes, for example, a normal electric motor or ultrasonic motor, and rotates the condenser mirror. At this time, if the rotating shaft is lifted and rotated by a magnetic force, or if the shaft is not mechanically contacted by an air bearing, vibration due to the rotation of the condenser mirror 22 does not have to propagate to the light source device 200 main body or the exposure device. . In FIG. 7, the arrows described above the first condenser mirror driving unit 28, the second condenser mirror driving unit 30, the third condenser mirror driving unit 32, and the fourth condenser mirror driving unit 38 are The moving direction of the condensing mirror 22 is shown, and the arrows described below the first light source driving unit 34 and the second light source driving unit 36 indicate the moving direction of the discharge generation plasma light source 20.

  As shown in FIG. 8, in this projection exposure apparatus, the light intensity distribution after passing through the aperture AP changes by rotating the condenser mirror 22 around the reference axis X. FIG. 9 shows the light intensity distribution of the light flux after passing through the aperture when the condensing mirror 22 is at the “rotation angle A” that is the first rotation position, and the condensing mirror 22 is the second rotation position. The light intensity distribution of the light beam after passing through the aperture when it is at the “rotation angle B” is shown.

  Therefore, under the control of the light source control unit 26 based on the control signal from the control unit 24, the control unit 24 causes the fourth condenser mirror to irradiate the EUV light emitted from the discharge generation plasma light source 20 onto the wafer W. When a control signal is output to the drive unit 38 and exposure is performed while rotating the condenser mirror 22 around the reference axis X, the intensity at which one point on the wafer W is exposed is obtained by superimposing these various light intensity distributions. As a result, the steep change in the light intensity distribution incident on the incident-side reflection type fly-eye mirror 6 constituting the fly-eye optical system is alleviated, and the shaded portion of the oblique incidence mirror is smoothed to perform uniform exposure. it can.

The rotational speed of the condensing mirror 22 is preferably such that the condensing mirror 22 rotates at least once or an integral multiple within the time during which one point on the wafer W receives exposure light. Therefore,
w: exposure width in the scan direction on the wafer [mm]
v: Wafer stage scan speed [mm / sec]
n: The number of divisions in the radial direction of the mirror
Period = (n · w) / v [sec]
Frequency = v / (n · w) [Hz]
It becomes.

  For example, when the exposure width in the scanning direction on the wafer W is 2 mm and the scanning speed of the wafer stage WS is 100 mm / sec, the time during which one point on the wafer W is receiving the exposure light is 2/100 = 20 msec. . Therefore, the condensing mirror 22 may be rotated once in a cycle shorter than at least 20 msec. When the rotational speed is set, the condenser mirror 22 may be rotated at 50 rps = 3000 rpm or more. If sufficient exposure amount can be uniformized with a shorter period than this, the rotation speed may be lower than the above rotation speed.

  Moreover, it is difficult to manufacture a grazing incidence mirror configured in a nested manner, and it is particularly difficult to manufacture and hold a cylindrical grazing incidence mirror in a perfect circle. Therefore, the shape of the shadow portion of the oblique incidence mirror is different for each condenser mirror. For this reason, when the condenser mirror is replaced, the shape of the shadow is different from that before the replacement, so that the same optical performance (for example, illuminance unevenness on the reticle) cannot be achieved. Therefore, when the condensing mirror is rotated around the reference axis X as described above, the shape of the shadow of the oblique incidence mirror is also rotated. Therefore, if these are overlapped, a perfect circular shadow can be formed. That is, in this case, it is only necessary to manufacture the oblique incidence mirror so that the deviation width from the perfect circle of each oblique incidence mirror is within a certain range, and the production of the oblique incidence mirror can be greatly simplified.

  In the second embodiment, the condensing mirror 22 composed of oblique incidence mirrors arranged in a nested manner is used, but the condensing mirror composed of a multilayer film mirror composed of a plurality of partial mirrors. May be used. For example, when the multi-layer mirror 40 is used, which is composed of partial mirrors 40a that are divided into eight in the radial direction as shown in FIG. 10, one point on the wafer W receives exposure light. Since 1/8 rotation may be performed in between, the rotation speed may be 1/8 of the above value, that is, 6.25 rps = 375 rpm or more. The rotation speed may be constant or may be rotated while changing the speed at random. Further, it may be correlated with the pulse repetition frequency of the light source. For example, when the repetition frequency is changed, the rotation speed is changed accordingly, the ratio between the rotation frequency and the repetition frequency is an integral multiple, or it is intentionally removed from the integral multiple relationship. Good.

  Further, by using the rotation of the condenser mirror 22 together with the movement of the condenser mirror 22 in the direction of the reference axis X, the movement of the condenser mirror 22 in the direction perpendicular to the reference axis X, or the inclination with respect to the reference axis X, post-condensing It is also possible to smooth the light intensity distribution of the beam pattern.

  Next, a projection exposure apparatus according to a third embodiment of the present invention will be described with reference to the drawings. FIG. 11 is a diagram showing a schematic configuration of the light source device 202 of the projection exposure apparatus according to this embodiment. In the description of the third embodiment, a detailed description of the same configuration as that of the projection exposure apparatus according to the first embodiment is omitted, and the projection exposure apparatus according to the first embodiment is omitted. The same components will be described using the same reference numerals.

  The projection exposure apparatus includes a light source device 202 instead of the light source device 2 of the projection exposure apparatus according to the first embodiment. As shown in FIG. 10, the light source device 202 includes a multilayer mirror 40 configured as a set of a plurality of partial mirrors 40a, and the partial mirrors 40a are tilted on the back side of each partial mirror 40a. A piezo element 42 is installed. In addition, a reflection member driving unit 44 is connected to the control unit 24, and a control signal is output to each piezo element 42 to control the tilt amount of each partial mirror.

  As shown in FIG. 11, in this projection exposure apparatus, after changing the shape of the multilayer mirror 40 itself by changing the tilt amount of the partial mirror 40a constituting the multilayer mirror 40, it passes through the aperture AP. The light intensity distribution is changed. FIG. 12 shows the shape of the multilayer mirror 40 at “time A” that is the first time, and the shape of the multilayer mirror 40 at “time B” that is the second time. Instead of changing the position of the entire mirror as described above, the light intensity distribution after accumulating a predetermined number of pulses by changing the shape of the multilayer mirror 40 itself and changing the beam pattern shape after focusing. Can be alleviated. For example, the multilayer mirror 40 divided into eight as shown in FIG. 10 is also reflected on the shadow portion of the partial mirror 40a by changing the tilt amount of each partial mirror 40a for each pulse during exposure of the wafer W. When the light arrives, the illuminance distribution after the condensing point when the predetermined number of pulses is integrated becomes uniform, and smoothing by the fly-eye mirror acts effectively, and the illuminance distribution on the mask M is reduced. It can be uniform. In the above embodiment, the partial mirror 40a is tilted. However, the partial mirror 40a may be moved in a direction parallel to the reference axis direction or perpendicular to the reference axis.

  In the above-described embodiment, the collimator mirror 4, the incident-side reflection type fly-eye mirror 6, the emission-side reflection type fly-eye mirror 8, the incident-side reflection type condenser mirror 10, and the emission-side reflection type capacitor mirror 12 are used as spherical mirrors. However, you may comprise by a rotation paraboloid mirror, a rotation ellipsoidal mirror, etc.

  In the above-described embodiment, a multilayer film is formed on the reflection surface of the collimator mirror 4, but the incident-side reflection fly-eye mirror 6, the emission-side reflection fly-eye mirror 8, and the incident-side reflection capacitor mirror. Similarly to the collimator mirror 4, a multilayer film in which a plurality of substances of molybdenum, ruthenium, rhodium, silicon, and silicon oxide are deposited may be formed on the 10 and the emission-side reflective capacitor mirror 12 as well.

  In the above-described embodiment, the reflective fly-eye optical system is configured by the incident-side reflective fly-eye mirror 6 and the exit-side reflective fly-eye mirror 8. However, the reflective fly-eye optical system is configured. The number of mirrors is not limited to two, and three or more can be selected as appropriate. Even in this case, it is desirable to configure the fly-eye optical system with as few as possible in order to minimize the light loss.

  In each of the above-described embodiments, the condenser optical system is configured by the incident-side reflective condenser mirror 10 and the outgoing-side reflective condenser mirror 12, but the number of mirrors constituting the reflective condenser optical system is as follows. The number is not limited to two, and may be one, or three or more can be selected as appropriate. In this case as well, it is desirable to configure the condenser optical system with as few as possible in order to minimize the light loss.

  In the exposure apparatus according to each of the above-described embodiments, the reticle (mask) is illuminated by the illumination optical system, and the transfer pattern formed on the mask is exposed to the photosensitive substrate (wafer) using the projection optical system ( By the exposure step, a micro device (semiconductor element, imaging element, liquid crystal display element, thin film magnetic head, etc.) can be manufactured. FIG. 13 shows an example of a technique for obtaining a semiconductor device as a micro device by forming a predetermined circuit pattern on a wafer or the like as a photosensitive substrate using the exposure apparatus according to each of the embodiments described above. This will be described with reference to a flowchart.

  First, in step S301 in FIG. 13, a metal film is deposited on one lot of wafers. In the next step S302, a photoresist is applied on the metal film on the wafer of one lot. Thereafter, in step S303, using the exposure apparatus according to each of the above-described embodiments, the pattern image on the mask is sequentially exposed and transferred to each shot area on the wafer of one lot via the projection optical system. The Thereafter, in step S304, the photoresist on the one lot of wafers is developed, and in step S305, the resist pattern is etched on the one lot of wafers to form a pattern on the mask. Corresponding circuit patterns are formed in each shot area on each wafer.

  Thereafter, a device pattern such as a semiconductor element is manufactured by forming a circuit pattern of an upper layer. According to the above-described microdevice manufacturing method, since exposure is performed using the exposure apparatus according to each of the above-described embodiments, it is possible to prevent a decrease in resolving power or contrast on the photosensitive substrate, and an extremely fine circuit A microdevice having a pattern can be obtained with high accuracy. In steps S301 to S305, a metal is vapor-deposited on the wafer, a resist is applied on the metal film, and exposure, development, and etching processes are performed. Prior to these processes, on the wafer. It is needless to say that after forming a silicon oxide film, a resist may be applied on the silicon oxide film, and steps such as exposure, development, and etching may be performed.

  In the exposure apparatus according to each of the above-described embodiments, a liquid crystal display element as a micro device can be obtained by forming a predetermined pattern (circuit pattern, electrode pattern, etc.) on a plate (glass substrate). . Hereinafter, an example of the technique at this time will be described with reference to the flowchart of FIG. In FIG. 14, in the pattern formation step S401, a so-called photolithography step is performed in which the mask pattern is transferred and exposed to a photosensitive substrate (such as a glass substrate coated with a resist) using the exposure apparatus according to each of the above embodiments. Executed. By this photolithography process, a predetermined pattern including a large number of electrodes and the like is formed on the photosensitive substrate. Thereafter, the exposed substrate undergoes steps such as a developing step, an etching step, and a resist stripping step, whereby a predetermined pattern is formed on the substrate, and the process proceeds to the next color filter forming step S402.

  Next, in the color filter forming step S402, a large number of groups of three dots corresponding to R (Red), G (Green), and B (Blue) are arranged in a matrix or three of R, G, and B A color filter is formed by arranging a plurality of stripe filter sets in the horizontal scanning line direction. Then, after the color filter formation step S402, a cell assembly step S403 is executed. In the cell assembly step S403, a liquid crystal panel (liquid crystal cell) is assembled using the substrate having the predetermined pattern obtained in the pattern formation step S401, the color filter obtained in the color filter formation step S402, and the like. In the cell assembly step S403, for example, liquid crystal is injected between the substrate having the predetermined pattern obtained in the pattern formation step S401 and the color filter obtained in the color filter formation step S402, and a liquid crystal panel (liquid crystal cell ).

  Thereafter, in a module assembly step S404, components such as an electric circuit and a backlight for performing a display operation of the assembled liquid crystal panel (liquid crystal cell) are attached to complete a liquid crystal display element. According to the above-described method for manufacturing a liquid crystal display element, since exposure is performed using the exposure apparatus according to each of the above-described embodiments, it is possible to prevent a decrease in resolving power, contrast, and the like on the photosensitive substrate. A semiconductor device having a simple circuit pattern can be obtained with high accuracy.

It is a figure which shows schematic structure of the projection exposure apparatus concerning 1st Embodiment. It is a figure which shows schematic structure of the light source device concerning 1st Embodiment. It is a front view of the incidence side reflection type fly's eye mirror concerning a 1st embodiment. It is a front view of the radiation | emission side reflection type fly's eye mirror concerning 1st Embodiment. It is a figure for demonstrating the movement of the reference | standard axis direction of the condensing mirror of the light source device concerning 1st Embodiment. It is a figure for demonstrating the light intensity distribution which changes with the movement of the reference | standard axis direction of the condensing mirror of the light source device concerning 1st Embodiment. It is a figure which shows schematic structure of the light source device concerning 2nd Embodiment. It is a figure for demonstrating rotation around the reference axis of the condensing mirror of the light source device concerning 2nd Embodiment. It is a figure for demonstrating the light intensity distribution which changes by the rotation around the reference axis of the condensing mirror of the light source device concerning 2nd Embodiment. It is a figure which shows the shape of the multilayer film mirror concerning embodiment. It is a figure which shows schematic structure of the light source device concerning 3rd Embodiment. It is a figure which shows the change of the shape of the multilayer mirror of the light source device concerning 3rd Embodiment. It is a flowchart which shows the manufacturing method of the semiconductor device as a microdevice concerning embodiment of this invention. It is a flowchart which shows the manufacturing method of the liquid crystal display element as a microdevice concerning embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2,200,202 ... Light source device, 4 ... Collimator mirror, 6 ... Incident side reflection type fly eye mirror, 8 ... Emission side reflection type fly eye mirror, 10 ... Incident side reflection type capacitor mirror, 12 ... Emission side reflection type capacitor Mirror, 20 ... Discharge generation plasma light source, 22 ... Condensing mirror, 24 ... Control unit, 26 ... Light source control unit, 28 ... First condensing mirror driving unit, 30 ... Second condensing mirror driving unit, 32 ... Third Condenser mirror drive unit 34 ... first light source drive unit 36 ... second light source drive unit 38 ... fourth collective mirror drive unit 40 ... multilayer film mirror 42 ... piezo element 44 ... M ... mask MS: mask stage, PL: projection optical system, W: wafer, WS: wafer stage, S: shutter, F: wavelength selection filter.

Claims (13)

A light source unit having a light source that generates extreme ultraviolet light and a condensing mirror that reflects and collects the extreme ultraviolet light emitted from the light source; and a mask using the extreme ultraviolet light emitted from the light source unit as illumination light In an exposure apparatus that illuminates and exposes a pattern of the mask on a photosensitive substrate,
An exposure apparatus comprising: removal means for removing a light intensity distribution of a non-uniform reflected light beam generated due to the structure of the condenser mirror.   2. The exposure apparatus according to claim 1, wherein the removing unit removes a non-uniform light intensity distribution of the reflected light beam caused by a shadow caused by a non-reflecting portion of the condenser mirror.   The removing means moves the condensing mirror in a reference axis direction that is a center of a light beam emitted from the condensing mirror during irradiation of the extreme ultraviolet light on the photosensitive substrate. The exposure apparatus according to claim 1 or 2.   The removing means moves the condenser mirror in a direction perpendicular to a reference axis that is a center of a light beam emitted from the condenser mirror during irradiation of the extreme ultraviolet light onto the photosensitive substrate. The exposure apparatus according to any one of claims 1 to 3.   The removing means tilts the condenser mirror with respect to a reference axis that is a center of a light beam emitted from the condenser mirror during irradiation of the extreme ultraviolet light onto the photosensitive substrate. The exposure apparatus according to any one of claims 1 to 4.   The removing means rotates the condensing mirror around a reference axis that is a center of a light beam emitted from the condensing mirror during irradiation of the extreme ultraviolet light on the photosensitive substrate. The exposure apparatus according to any one of claims 1 to 5.   2. The removal means moves the light source in a reference axis direction that is a center of a light beam emitted from the condenser mirror during irradiation of the extreme ultraviolet light onto the photosensitive substrate. The exposure apparatus according to claim 6.   The removing means moves the light source in a direction perpendicular to a reference axis that is a center of a light beam emitted from the condenser mirror during irradiation of the extreme ultraviolet light onto the photosensitive substrate. The exposure apparatus according to any one of claims 1 to 7. The condensing mirror has a plurality of reflecting members,
9. A reflection member driving unit that changes at least one posture of the plurality of reflection members during irradiation of the extreme ultraviolet light on the photosensitive substrate is provided. The exposure apparatus according to item. The removing means is configured to irradiate the photosensitive substrate with the extreme ultraviolet light,
A condenser mirror attitude changing means for changing the attitude of the condenser mirror;
The exposure apparatus according to claim 1, further comprising a light source position changing unit that changes a position of the light source. The collector mirror changing means is irradiating the extreme ultraviolet light on the photosensitive substrate,
A direction of a reference axis that is a center of a light beam emitted from the light collecting mirror, a direction perpendicular to the reference axis, a direction in which the light collecting mirror is inclined with respect to the reference axis, And moving the condenser mirror in at least one of the directions of rotating around the reference axis,
The light source position changing means, while irradiating the photosensitive substrate with the extreme ultraviolet light,
The exposure apparatus according to claim 10, wherein the light source is moved in at least one of the reference axis direction and a direction perpendicular to the reference axis. The condensing mirror has a plurality of reflecting members,
12. The exposure according to claim 10, further comprising a reflection member driving unit that changes at least one posture of the plurality of reflection members during irradiation of the extreme ultraviolet light on the photosensitive substrate. apparatus. A method of manufacturing a microdevice using the exposure apparatus according to any one of claims 1 to 12,
An exposure step of exposing the pattern of the mask onto the photosensitive substrate;
And a development step of developing the photosensitive substrate exposed in the exposure step.

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