JP2012003815A - Laser exposure apparatus and method - Google Patents

Abstract

The present invention provides a laser exposure apparatus in which the mass of a focus actuator driving unit is reduced and the followability is improved.
A collimated laser beam L is condensed on a reflective substrate 123 movable in the optical axis direction by a condenser lens 122 through a polarizing beam splitter 120 and a quarter-wave plate 121. The reflected light from the reflective substrate 123 is again converted into collimated light through the condenser lens 122 and then incident on the fixed objective lens 110. Focusing is performed by controlling the movement of the reflective substrate 123 in the optical axis direction based on the defocus information. In this way, the reflective substrate 123 with a small mass is driven instead of the objective lens 110 with a large mass.
[Selection] Figure 1

Description

  The present invention relates to a laser exposure apparatus and method applied to an exposure apparatus for producing a master of an optical disk such as a CD, a DVD or a BD (Blu-ray Disc), or an exposure apparatus using a nanoimprint technology.

  In the production of an optical disk, a stamper is made from a master, and duplication is performed by injection molding using this stamper to produce an optical disk.

  An exposure apparatus for creating an optical disc master used to create this master disc modulates and deflects a coherent beam emitted from a light source, and irradiates the optical disc master with recording light through an objective lens. Is used to record information (for example, see Patent Document 1).

  FIG. 9 is a schematic block diagram of a general master exposure apparatus.

  In FIG. 9, the laser light L generated from the laser light source unit 101 passes through a beam modulation unit 102, a beam deflection unit 103, and a beam shaping unit 104, and is shaped into parallel light (collimated light). Thereafter, the laser light L is reflected by the mirror 105 and the half mirror 106, passes through the half mirror 108, passes through the objective lens 110 driven by the actuator 110 a from the dichroic mirror 109, and is collected on the glass master 111.

  The laser light L reflected from the master 111 travels in the opposite direction to that described above, and part of the laser light L passes through the half mirror 106 and then enters the beam monitor system 107. In the beam monitor system 107, the laser light L passes through the convex lens 107a and is condensed on the detector 107b.

  The convex lens 107 a and the detector 107 b are adjusted in advance to a positional relationship in which the laser light L is focused on the focus point of the objective lens 110 by the objective lens 110.

  That is, when the condensed beam is minimized on the detector 107b, the laser light L that has passed through the objective lens 110 is also just focused, and exposure is performed while maintaining such a state, so that a desired pit width and length can be obtained. Thus, an optical disc master that satisfies the requirements and the continuous groove width can be obtained.

  In order to maintain the just focus state, an auxiliary focus servo optical system 117 shown in FIG. 9 is generally used. When the auxiliary focus servo optical system 117 is used, the laser light emitted from the auxiliary focus servo optical system 117 passes through the dichroic mirror 109 and the objective lens 110 by the mirror 116 and then enters the master 111. The reflected light reflected from the surface of the master 111 again passes through the objective lens 110 and the dichroic mirror 109, is reflected by the mirror 116, and enters the auxiliary focus servo optical system 117, thereby enabling focus servo detection.

  In recent years, technologies related to optical discs are required to have high quality in addition to high accuracy such as BD (Blu-ray Disc). Along with this, it is also required for the master recording device to improve the precision of components such as spindles and sliders and to improve its control performance, and also for the focus servo, high precision and high followability are required. ing.

  Considering the productivity of master recording, the recording speed has been increasingly demanded as the recording speed has increased to 2x and 3x in conventional CDs and DVDs. In addition, high frequency tracking is required.

  In the conventional master recording apparatus, as shown in FIG. 10, the objective lens 110 is housed in a housing 140 that is as small as possible, and on the one hand, the housing 140 is held by static pressure to serve as a guide in the vertical direction. A method of attaching and driving a voice coil to the housing 140 has been used. That is, the structure which moves objective-lens 110 itself is employ | adopted, and it was set as the structure where an operation | movement part became light as much as possible in order to maintain high tracking property by this method.

  In order to improve the performance of the focus servo, not only the auxiliary laser beam but also the recording light reflected from the master 111 is directly used for the focus servo. For example, a part of the reflected light from the master 111 is branched using the half mirror 108 shown in FIG. 9 and incident on the recording beam focus servo system 113 via the mirror 112, thereby realizing a more precise focus servo. A method has been proposed.

  Further, regarding the downsizing of the exposure apparatus, the beam modulation unit 102 and the beam shaping unit 104 can be omitted by using a semiconductor laser for the light source 101 in FIG.

JP 2000-48412 A

  The precision required for the master in the production of optical discs is strict, and in particular, in the case of a Blu-ray disc for high vision, finer and higher precision laser exposure is required. For fine and highly accurate exposure, high precision is required for each part in the laser exposure apparatus. Of particular importance is the characteristics of the laser beam in the laser exposure apparatus.

  However, on the other hand, as the master recording becomes more precise, the objective lens that ultimately affects the characteristics of the laser beam needs to have a large aperture and a high numerical aperture (NA) in order to prioritize the aperture, which increases the weight. Has become an unavoidable problem.

  This also hinders exposure due to high recording speed, that is, high rotation speed, that is, high rotation. Furthermore, there is a problem that a large cost is required to reduce the diameter of the objective lens or to realize a lightweight objective lens.

  In addition, due to the practical use of blue semiconductor lasers with excellent laser quality, the power control and on / off modulation of laser light can be performed from the inside of the optical system of the exposure apparatus from an electro-optic modulator (EO modulator), acousto-optic modulator ( Although the omission of the (AO modulation element) could be realized, the wobbling mainly used for the recording medium, that is, the angle control in the vertical direction with respect to the optical axis of the laser beam using the laser deflection element. As in the prior art, it is necessary to provide a deflecting element in the exposure apparatus, which also hinders the reduction in size and weight of the optical system in the apparatus.

  It is an object of the present invention to provide a laser exposure apparatus and method that can solve the problems of the prior art and reduce the mass of the focus actuator drive unit and improve the followability.

  In order to solve the above problems, a laser exposure apparatus according to the present invention includes a laser light source unit that emits laser light and an objective lens that focuses the laser light on an object. A reflection member installed on the optical axis of the laser beam; a condenser lens for condensing the laser beam on the reflection member; and And a moving means for moving in the axial direction.

  According to the present invention, it is possible to reduce the mass of the focus actuator driving unit and dramatically improve the followability of the focus of the laser beam.

The perspective view which shows the structure of the optical system of the objective lens part of Embodiment 1 of this invention. The perspective view which shows the structure of the optical system of the objective lens part of Embodiment 2 of this invention. The perspective view which shows the structure of the optical system of the objective lens part of Embodiment 3 of this invention. Schematic explanatory diagram of the optical disc mastering process in the embodiment of the present invention 1 is a schematic configuration diagram of an entire apparatus according to an embodiment of the present invention. Explanatory drawing which shows the detail of the recording beam focus servo system in embodiment of this invention Explanatory drawing which represented typically the laser beam of each state which permeate | transmits and reflects a polarizing beam splitter in embodiment of this invention Sectional drawing which shows the structure of the board | substrate moving means using the hydrostatic bearing of embodiment of this invention Schematic block diagram of a conventional general master exposure apparatus The perspective view which shows the structure of the optical system of the objective lens part in the conventional master exposure apparatus

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
First, an outline of the optical disc mastering process in the laser exposure apparatus of the present invention will be described based on the explanatory diagram of the mastering process in FIG.

  First, a glass plate is polished to form an optical disc mastering master (step a). As a material for the master for optical disc mastering, blue plate glass (soda lime glass), quartz glass, Si substrate or the like is used.

  Next, a photoresist made of an organic material is formed on the master by spin coating, or an inorganic recording material is formed by a sputtering method (step b). The thickness of the photoresist or the recording material is about 10 to 300 nm, although it varies depending on the format such as CD, DVD, BD and / or the reflective film or recording material used in the disc.

  Next, signal pits and / or guide grooves are drawn and recorded on the master disk by a laser from an optical recording device (step c). Thereafter, the exposed portion is developed with an alkali developer (step d), so that only the exposed portion is eluted, and a concavo-convex pattern and / or groove as a desired pit shape is formed.

  Subsequently, a conductive film is formed on the exposed master surface by sputtering or electroless method (step e), and nickel electroforming is performed (step f), whereby a stamper for optical disc mastering is manufactured.

  When an inorganic recording material is formed on the master by sputtering in step b, the conductive film forming step in step e may be omitted.

  Mother stamping of the master stamper manufactured as described above, that is, nickel electroforming is performed twice on the stamper (step g and step h), thereby completing a stamper for optical disc injection molding. Note that step g and step h may be omitted.

  FIG. 5 is a schematic block diagram of the entire optical disc master exposure apparatus as an embodiment of the laser exposure apparatus of the present invention.

  In FIG. 5, the laser light L emitted from the laser light source unit 101 passes through the beam modulation unit 102 and is output after being frequency-deflected in the horizontal and vertical directions perpendicular to the optical axis with respect to the beam deflection unit 103. The laser light L emitted from the beam deflecting unit 103 is shaped into parallel light (collimated light) of an appropriate size by the beam shaping unit 104, reflected by the mirrors 105 and 106, transmitted through the half mirror 108, and transmitted through the dichroic mirror 109. Then, the light enters the fixed objective lens 110.

  The light incident on the objective lens 110 is collected on the master 111 and is irradiated on the resist layer 111 a formed on the master 111. At this time, the laser beam L irradiated onto the master 111 through the objective lens 110 is focused on the master 111, and when the resist layer 111a is an organic resist layer, the photolithography method is used, and the resist layer 111a is inorganic. In the case of a resist layer, exposure is performed by a thermal recording method.

  The recording laser light L emitted from the laser light source unit 101 is sufficient for the wavelength at which the organic resist layer is exposed when the wavelength is the photolithography method, and is sufficient for the inorganic resist layer when the thermal recording method is used. A wavelength that gives a sufficient heat energy, for example, 375 nm or 405 nm is used.

  In this configuration, the beam deflection unit 103 and the beam shaping unit 104 may be omitted.

  Next, the laser beam L reflected from the master 111 passes through the objective lens 110 again, is reflected by the dichroic mirror 109, passes through the half mirror 108 and the mirror 106, and then enters the beam monitor system 107. In the beam monitor system 107, the laser light L passes through the convex lens 107a and is condensed on the detector 107b.

  The convex lens 107 a and the detector 107 b of the beam monitor system 107 are adjusted in advance to the positional relationship in which the laser light L is focused on the focus point of the objective lens 110 by the objective lens 110.

  That is, when the spot of the laser beam condensed on the detector 107b is minimized, the laser beam L transmitted through the objective lens 110 is also just focused. By performing exposure while maintaining such a state, an optical disc master satisfying a desired pit width, length and / or continuous groove width can be obtained.

  In this embodiment, in order to realize high-performance focus servo, the reflected light of the laser light L from the master 111 is transmitted through the dichroic mirror 109 and incident on the reflective substrate 123 as described later, and the half mirror 108 Is used, and an optical system that enters the recording beam focus servo system 113 via a mirror 112 is used.

  FIG. 1 is a perspective view showing a configuration of an optical system of an objective lens portion of an optical disc master exposure apparatus according to Embodiment 1 of the present invention.

  In FIG. 1, a parallel (collimated) laser beam L is incident on the polarization beam splitter 120 and is laterally polarized. Then, the laser beam L is reflected by the polarization beam splitter 120 and transmitted through the quarter-wave plate 121 and further transmitted through the condenser lens 122 and condensed. A reflective substrate 123, which is a reflective member that can move in the direction of the optical axis, is installed at this condensing position. Here, when the numerical aperture of the condensing lens 122 is the same as the numerical aperture of the objective lens 110, the control condition becomes simple and the control becomes easy.

  By providing the focal point of the condenser lens 122 on the reflective substrate 123, the condensed laser light L is reflected by the reflective substrate 123, travels backward on the same optical axis as above, and passes through the condenser lens 122 again. By doing so, it becomes parallel light and passes through the quarter-wave plate 121. Here, by passing through the quarter-wave plate 121 twice, the laser light L changes from horizontally polarized light to vertically polarized light. For this reason, the laser light L re-entering the polarizing beam splitter 120 passes through the polarizing beam splitter 120, travels in the direction of the fixed objective lens 110, passes through the objective lens 110, and becomes the focal point of the objective lens 110. Focused.

  The focus position of the objective lens 110 is set in advance so as to be positioned on the surface of the master 111. That is, when the parallel laser beam L is incident, the focus servo is configured so that both the optical surface is focused on the surface of the reflective substrate 123 and the surface of the master 111.

  Here, it is assumed that the surface of the master 111 has irregularities and the point collected by the objective lens 110 is displaced from the master 111 toward the objective lens 110 due to the rotation of the master 111 or the like. At this time, the reflected light of the laser beam L from the master 111 again enters the polarization beam splitter 120 as a converged light without being converted into a parallel light even when passing through the objective lens 110. This incident light travels in the opposite direction as the optical path so far as return light, and is focused on the condenser lens 122 side by the condenser lens 122 from the surface of the reflective substrate 123.

  Further, the light reflected by the reflective substrate 123 again passes through the condensing lens 122 and becomes focused light, and then passes through the quarter-wave plate 121 twice. To Penetrate. That is, the laser light L travels in the reverse direction along the incident optical path while remaining as focused light.

  In FIG. 1, a part of the laser light L reflected and returned from the master 111 is reflected by the half mirror 108 in FIG. 5 and enters the recording beam focus servo system 113.

  FIG. 6 is an explanatory diagram showing details of the recording beam focus servo system 113 in FIG.

  5 and 6, the laser beam L incident on the recording beam focus servo system 113 is guided to a condensing lens 113a, a cylindrical lens 113b, and a four-divided detector 113c constituting the astigmatism optical system.

  In the present embodiment, settings are made as follows. When the laser beam L incident on the recording beam focus servo system 113 is collimated light, a setting is made so that a circular spot is formed on the quadrant detector 113c, as indicated by 113c-1 in FIG. 6B. . When the laser beam L incident on the recording beam focus servo system 113 is divergent light, a spot long in the axial direction of the cylindrical lens 113b on the quadrant detector 113c, as indicated by 113c-2 in FIG. 6B. Is set to be formed. Further, when the laser beam L incident on the recording beam focus servo system 113 is a focused beam, as indicated by 113c-3 in FIG. 6B, it is perpendicular to the axis of the cylindrical lens 113b on the quadrant detector 113c. It is set so that a long spot is formed in any direction.

  In the present embodiment, as shown in FIG. 6A, the light amounts received by the light receiving portions a, b, c, and c of the quadrant detector 113c are a, b, c, and d, and S = {( A feedback control mechanism 114 is provided for controlling the position of the reflective substrate 123 in FIG. 1 in accordance with the value of S in (a + c) − (b−d)} / (a + b + c + d).

  FIG. 7 is an explanatory view schematically showing laser light in each state of being transmitted and reflected through the polarizing beam splitter. FIG. 7A shows an optical axis of the laser light in the polarizing beam splitter portion, and FIG. FIG. 7B shows the optical axis of the laser beam in the horizontal direction in the recording beam focus servo system, and FIG. 7C shows the optical axis of the laser beam in the vertical direction in the recording beam focus servo system.

  In FIG. 7, when the laser light L is collimated light, L1 is shown, when L2 is focused light, and L3 is shown when it is divergent light.

  For example, when the laser beam L is focused light L2, the condenser lens 113a and the cylindrical lens 113b are focused at the position 113c-3 in FIGS. 7B and 7C. The laser beam shape on the split detector 113c is a long spot in a direction perpendicular to the axis of the cylindrical lens 113b, as shown in FIG. 6B.

  Here, the position of the reflective substrate 123 in FIG. 1 is controlled by the feedback control mechanism 114 according to the value of S by the substrate moving means (described later). In this case, since S is negative, the reflecting substrate 123 is moved in a direction approaching the condenser lens 110.

  When the reflecting substrate 123 moves in the direction of the condenser lens 110, the light incident on the polarization beam splitter 120 changes from parallel light to divergent light, reflects the polarization beam splitter 120, and enters the objective lens 110. L also changes from parallel light to divergent light. Therefore, the focal point originally shifted toward the objective lens 110 side due to the unevenness on the surface of the rotating master 111 moves in the direction of the master 111.

  On the other hand, in the case where the focal point is far from the master 111 due to the unevenness of the master 111, the laser light L reflected from the master 111 and transmitted through the objective lens 110 becomes divergent light L3, and the polarization beam splitter 120 and The light is guided to the condensing lens 122 and squeezed so as to focus on a position farther than the reflective substrate 123. After the reflected light from the reflective substrate 123 passes through the condenser lens 122, this also becomes divergent light. That is, the reflected light from the master 111 finally becomes divergent light and is reflected by the half mirror 108.

  In this case, a spot formed on the quadrant detector 113c is a long spot in a direction parallel to the axis of the cylindrical lens 113b on the quadrant detector 113c of 113c-2 shown in FIG. 6B.

  In FIG. 7, since the condenser lens 113a and the cylindrical lens 113b are focused at the position 113c-2, the spot shape on the quadrant detector 113c is a long spot in a direction parallel to the axis of the cylindrical lens 113b. .

  At this time, if S = {(a + c) − (b−d)} / (a + b + c + d) is calculated in the same manner as described above, the value of S becomes positive. Therefore, in this case, when the position of the reflective substrate 123 in FIG. 1 is controlled, the reflective substrate 123 moves in a direction away from the condenser lens 110, contrary to the above.

  When the reflective substrate 123 moves away from the condenser lens 110, when the reflected light from the reflective substrate 123 is transmitted again through the condenser lens 122, it changes from the parallel light so far to the converged light and is reflected by the polarizing beam splitter 120. Thus, the laser light L incident on the objective lens 110 also changes from parallel light to focused light. Accordingly, the focal point that is farther from the surface of the master 111 moves in the direction of the objective lens 110.

  In this way, by positioning the reflective substrate 123 using the value of S, it is possible to always form a focal point on the master 111 even with the objective lens 110 fixed.

  As the substrate moving means for driving the reflective substrate 123, a device using a hydrostatic bearing, a device using a piezoelectric element, or a combination thereof can be considered.

  FIG. 8 is a sectional view showing the configuration of the substrate moving means using the hydrostatic bearing in the present embodiment.

  In FIG. 8, in the substrate moving means 130, the reflective substrate 123 is fixed to the shaft 131 with high precision, and the hydrostatic bearing 132 and the shaft 131 constitute a linear motion guide. Further, by passing an electric current through the coil 133 wound around the shaft 131, a magnetic force is applied to the shaft 131, and an action is caused on the permanent magnet 134, thereby driving the shaft 131 up and down. Thereby, the reflective substrate 123 can be moved in the optical axis direction.

  Here, in the conventional exposure apparatus, the objective lens (formerly manufactured by Tropel (now Corning), super lens) has a diameter of about 16.4 mm × 25 mm and a weight of 20 g, and the mass of the housing that houses this lens. Was 25 g, and the voice coil and the lens fixing member were 5 g, so the minimum total of 50 g was the limit. However, in the drive portion in the present embodiment, specifically, the plane mirror can be 4 mm × 3 mm in diameter, the shaft can be 3 mm × 12 mm in diameter, and the weight of the movable portion can be at least 2 g or less. . Therefore, a weight of 1/25 is achieved as compared with the conventional case, and it is possible to improve the followability up to a frequency region five times as high as the conventional frequency characteristic.

  Further, when the aperture of the condenser lens 122, that is, when the NA value is made the same as that of the objective lens 110, the focal depths of the objective lens 110 and the condenser lens 122 are equal, and the focal position due to the focal depth of both. Deviations can be canceled.

(Embodiment 2)
FIG. 2 is a perspective view showing the configuration of the optical system of the objective lens portion of the optical disc master exposure apparatus according to Embodiment 2 of the present invention. In the following description, members corresponding to those described in the first embodiment are given the same reference numerals, and detailed description thereof is omitted.

  In FIG. 2, the parallel laser light L incident on the polarization beam splitter 120 is laterally polarized. Then, the laser beam L is reflected by the polarization beam splitter 120 and transmitted through the quarter-wave plate 121 and further transmitted through the condenser lens 122 and condensed. A reflective substrate 123, which is a reflective member that can move in the direction of the optical axis, is installed at this condensing position.

  By setting the focal point of the condensing lens 122 on the reflective substrate 123, the condensed laser light L is reflected by the reflective substrate 123 and travels backward on the same optical axis as described above, and again passes through the condensing lens 122. By being transmitted, it becomes parallel light and passes through the quarter-wave plate 121. Here, by passing through the quarter-wave plate 121 twice, the laser light L changes from horizontally polarized light to vertically polarized light. For this reason, the laser light L re-entering the polarization beam splitter 120 passes through the polarization beam splitter 120 and proceeds in the direction of the fixed objective lens 110, and becomes a quarter wavelength plate (second quarter wavelength plate). ) 124 and the objective lens 110 to be condensed at the focal point of the objective lens 110.

  The optical system is set in advance so that the focal position of the objective lens 110 is positioned on the surface of the master 111. That is, when the parallel laser beam L is incident, the focus servo is configured so that both the optical surface is focused on the surface of the reflective substrate 123 and the surface of the master 111.

  In the second embodiment, the laser light L reflected and returned from the master 111 again passes through the objective lens 110 and further passes through the quarter wavelength plate 124. In other words, the second embodiment is configured to pass through the quarter-wave plate 124 twice. By passing through the quarter-wave plate 124 twice, the laser light L again changes from vertical deflection to horizontal deflection, reenters the deflecting beam splitter 120, reflects, and enters the focus servo optical system 125. An optical system having the same configuration as that of the recording beam focus servo system 113 described with reference to FIGS. 5 to 7 is provided in the focus servo optical system 125, and focus control is performed in the same manner as described above.

(Embodiment 3)
FIG. 3 is a perspective view showing the configuration of the optical system of the objective lens portion of the optical disc master exposure apparatus according to Embodiment 3 of the present invention.

  In FIG. 3, the parallel laser light L incident on the polarization beam splitter 120 is laterally polarized. Then, the laser beam L is reflected by the polarization beam splitter 120 and transmitted through the quarter-wave plate 121 and further transmitted through the condenser lens 122 and condensed. A reflective substrate 123, which is a reflective member that can move in the direction of the optical axis, is installed at this condensing position.

  In the third embodiment, a laser beam angle adjusting device 126 that is an angle adjusting unit is disposed between the condenser lens 122 and the reflective substrate 123, and the device controller 127 drives the laser beam angle adjusting device 126 to drive the optical axis. The angle is adjusted. The laser light L that has passed through the condensing lens 122 is condensed after passing through the laser beam angle adjusting device 126, reflected by the reflective substrate 123, travels backward on the same optical axis as before, and again adjusts the laser beam angle. The light passes through the device 126 and the condenser lens 122 to become parallel light.

  By passing the laser beam angle adjusting device 126 twice, the laser light L after exiting the condensing lens 122 enters the condensing lens 122 and remains at an angle with respect to the optical axis. The light passes through the four-wave plate 121.

  By passing through the quarter-wave plate 121 twice, the laser light L changes from laterally polarized light to longitudinally polarized light, re-enters the polarizing beam splitter 120, passes through, and passes through the fixed objective lens 110. Focused on the focal point. Here, the focusing of the objective lens 110 on the surface of the master 111 is controlled by displacing the reflective substrate 123 in the optical axis direction in the same manner as described above.

  In the third embodiment, the laser light L incident on the objective lens 110 has an angle with respect to the optical axis. Therefore, since the laser beam L is irradiated on the surface of the master 111 with an angle even after passing through the objective lens 110, the exposure position slightly changes. By making the direction of this angular displacement the radial direction of the master surface, it becomes possible to change the exposure position in the radial direction of the surface of the master 111, so that modulation such as wobbling can be performed.

  A thin film type electro-optic deflection element (EO deflection element) is used as the laser beam angle adjustment device 126, and the laser beam L is passed through the laser beam angle adjustment device 126 twice, thereby increasing the deflection angle amount. It becomes possible.

  As described above, according to the present embodiment, the collimated laser beam L is once squeezed onto the reflective substrate 123 movable in the optical axis direction by the condenser lens 122, and the reflected laser beam L is The light is again passed through the condenser lens 122 to be converted into parallel light, and then incident on the fixed objective lens 110. As a result, instead of the objective lens 110 having a large mass, only the reflective substrate 123 having a small mass is moved in the optical axis direction, thereby enabling high followability. Moreover, it is not necessary to consider the mass of the objective lens 110.

  Further, by forming a focus servo system between the condenser lens 122 and the objective lens 110, it is possible to perform precise focus servo without providing the optical system inside the exposure apparatus.

  Furthermore, a deflecting element is used in the optical system of the exposure apparatus by providing a laser beam angle adjusting device 126, which is a mechanism for adjusting an angle perpendicular to the optical axis of the laser light L, on the reflective substrate 123 or a part thereof. Therefore, the angle control of the laser beam L can be performed.

  The present invention can reduce the mass of the focus actuator driving unit, and can therefore greatly improve the followability. Further, the focus servo system and the deflecting element can be integrated into the actuator head portion, and can be omitted from the inside of the exposure apparatus optical system. Therefore, since the apparatus can be reduced in size, it can be applied to uses such as optical disc mastering and nano laser processing.

DESCRIPTION OF SYMBOLS 101 Laser light source part 102 Beam modulation part 103 Beam deflection part 104 Beam shaping part 107 Beam monitor system 107a Convex lens 107b Detector 108 Half mirror 109 Dichroic mirror 110 Objective lens 111 Master disk 112 Mirror 111a Resist layer 113 Recording beam focus servo system 113a Condensing lens 113b Cylindrical lens 113c Quadrant detector 114 Feedback control mechanism 120 Polarizing beam splitter 121 1/4 wavelength plate 122 Condensing lens 123 Reflecting substrate 124 1/4 wavelength plate 125 Focus servo optical system 126 Laser beam angle adjustment device 127 Device controller 130 Substrate Moving means 131 Shaft 132 Hydrostatic bearing 133 Coil 134 Permanent magnet L Laser light

Claims (8)

In a laser exposure apparatus comprising a laser light source unit that emits laser light and an objective lens that focuses the laser light on an object,
A reflecting member installed on the optical axis of the laser beam;
A condensing lens for condensing the laser light on the reflecting member;
A laser exposure apparatus comprising: moving means for moving the reflecting member in the optical axis direction based on laser beam defocus information with respect to the object. The laser exposure apparatus according to claim 1, wherein the condenser lens and the objective lens have the same numerical aperture. A polarization beam splitter disposed on the optical axis of the laser light from the laser light source unit;
3. The laser exposure apparatus according to claim 1, further comprising: a quarter-wave plate disposed between the polarizing beam splitter and the condenser lens on the optical axis. 4. The laser exposure apparatus according to claim 3, further comprising a second quarter-wave plate disposed between the deflecting beam splitter and the objective lens on the optical axis of the laser light. 4. An angle adjusting means that is disposed between the reflecting member and the condenser lens on the optical axis of the laser light and adjusts the angle of the optical axis of the laser light. The laser exposure apparatus described. 6. The laser exposure apparatus according to claim 5, wherein an electro-optic deflection element is installed as the angle adjusting means. The laser exposure apparatus according to claim 1, wherein the object is a disc master. 8. A laser exposure method, wherein the object is exposed using the laser exposure apparatus according to any one of claims 1 to 7.

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