JP6057583B2 - Optical scanning device and scanning inspection device - Google Patents

Description

  The present invention relates to an optical scanning device and a scanning type inspection device.

  Conventionally, there has been known a scanning optical microscope that can quickly move the observation surface in the depth direction of the sample by moving the focal position of the laser light in the optical axis direction of the laser light using a wavefront conversion element. (For example, refer to Patent Document 1).

JP 2004-109219 A

However, in Patent Document 1, the shape of the reflection surface of the wavefront conversion element is optimized for each focal position, and the observation surface is scanned one by one. Therefore, when observing a plurality of observation planes with different depth positions, a time difference occurs in the observation time of each observation plane for the time required for scanning at least one observation plane, and a plurality of observation planes with different depth positions are displayed. There is an inconvenience that scanning and observation cannot be performed simultaneously.
The present invention has been made in view of the above-described circumstances, and an object thereof is to provide an optical scanning device and a scanning inspection device capable of scanning a plurality of regions to be inspected at different depth positions substantially simultaneously. To do.

In order to achieve the above object, the present invention provides the following means.
The present invention provides a beam angle setting unit that gives a plurality of laser beams traveling on the same plane to a relative angle on the plane and collects the plurality of laser beams at the same location, and the beam angle setting unit. A scanning unit that scans the laser beams gathered at the same location in a direction along the plane, and a focusing optical system that forms a focal point by converging the laser beams scanned by the scanning unit; by adjusting the position of the focal point of each of the laser beams in the optical axis direction before Symbol laser beam formed by該合focusing optical system, the focus position to vary the position of at least a portion of the focal point on the optical axis An optical scanning device including an adjusting unit is provided.

  According to the present invention, the plurality of laser beams collected in the scanning unit by the beam angle setting unit are scanned by the scanning unit at a relative angle corresponding to the incident angle to the scanning unit. As a result, the plurality of laser beams are sequentially scanned in the same range in the plane along the scanning direction with a time interval.

  In this case, since the focal positions of the plurality of laser beams irradiated to the subject via the focusing optical system are different from each other in the optical axis direction by the focusing position adjusting means, the plurality of laser beams are mutually reflected on the subject. Different depth positions are scanned. The difference in time at which each laser beam is scanned at each depth position at this time is a sufficiently short time corresponding to the scanning period of the plurality of laser beams by the scanning unit. As a result, a plurality of regions to be inspected having different depth positions can be scanned substantially simultaneously.

In the above invention, the pair of laser beams are provided in series in front of the scanning unit, and each laser beam is emitted to the scanning unit as a substantially parallel light beam after a focus is formed on the plurality of laser beams at an intermediate position therebetween. comprising a lens system, the focal position adjusting means, the position of the focal point is formed between the pair of the lens system may be adjusted in the direction of the optical axis of the laser beams.
By doing in this way, the position of the focus of each laser beam formed by the focusing optical system in the optical axis direction can be made different with a simple configuration.

In the above invention, one of the pair of lens systems is a plurality of converging lens systems that are provided on an optical path of each of the laser beams and use the laser beams as a convergent light beam, and the focusing position adjusting unit However, the position in the optical axis direction in the optical path of each converging lens system may be adjusted.
By doing in this way, the focus position of each laser beam can be made different from each other independently and with a simple configuration.

Moreover, in the said invention, each said converging lens system may be provided so that a movement in the optical axis direction of each said laser is possible.
By doing in this way, the position of the focus of each laser beam can be changed independently and easily.

Moreover, in the said invention, the said focus position adjustment means may be provided between the said pair of lens systems, and may be provided with the optical path length adjustment part which adjusts the optical path length of each said laser beam.
By doing in this way, the focus position of each laser beam can be made different from each other independently and with a simple configuration.

In the invention described above, the branching portion provided between the pair of lens systems for branching the incident laser beam into two optical paths and the two optical paths branched by the branching portion are merged into one. The optical path length adjusting unit is provided with an angle with each other in the optical paths branched by the branch unit, and sequentially reflects the laser light incident from the branch unit and guides it to the junction unit. A pair of mirrors may be provided, and each of the pair of mirrors may be capable of changing an optical path length from the branch portion to the junction portion via the pair of mirrors.
By doing so, the two laser beams branched at the branching portion are given different optical path lengths by the pair of mirrors and then merged at the junction. Thereby, the structure of an optical path length adjustment part can be simplified.

In the above invention, the pair of mirrors may be provided so as to be integrally movable in a direction along the incident optical axis of the laser light incident from the branch portion.
By doing in this way, the position of the focus of two laser beams can be changed independently and easily.

In the above invention, the pair of mirrors may be provided so as to be integrally movable in a direction intersecting an incident optical axis of laser light incident from the branching portion.
By doing in this way, only the distance space | interval of the two laser beams merged in a merge part can be changed easily.

In the above invention, a plurality of sets of the pair of lens systems, the branching unit, the pair of mirrors, and the merging unit may be provided in series.
By doing so, the number of laser beams scanned by the scanning unit can be increased to 2, 4, 8,.

In the above invention, includes a collimating means for mutually parallel optical axes of the plurality of laser beams in front of one of said pair of lens systems, other of the pair of the lens system, the collimated A collimating lens system for commonly receiving the plurality of laser beams whose optical axes are parallel to each other by the means, and collecting the received plurality of laser beams at the same location, and the beam angle setting unit, It may consist of the collimating lens system.
By doing in this way, a collimating optical system can serve as a beam angle setting part, and can simplify a structure.

Moreover, in the said invention, you may provide the slit which restrict | limits the range of the scanning direction through which the said laser beam scanned by the said scanning part passes.
In this way, it is possible to irradiate the subject with a part of the plurality of laser beams scanned by the scanning unit while switching in order.

In the invention described above, another scanning unit that scans the laser beam scanned by the scanning unit in a direction orthogonal to a scanning direction by the scanning unit may be provided.
By doing in this way, a laser beam can be scanned two-dimensionally in the subject.

In the above invention, the in-focus position adjusting means sets the same focal position in the optical axis direction of some of the plurality of laser beams, and the other scanning unit includes: The some laser beams may be scanned at different positions in the orthogonal direction.
By doing so, a plurality of laser beams are scanned in order while shifting the position of the plane at the same depth position, so that the time required for scanning one inspection surface of the subject can be shortened. .
Moreover, in the said invention, the said focus position adjustment means may mutually vary the position of the focus of each said laser beam in the optical axis direction of the said laser beam.

  In addition, the present invention provides the optical scanning device according to any one of the above, an observation optical system that irradiates a subject with the laser light scanned by the optical scanning device, and the laser light is irradiated by the observation optical system. In addition, a scanning inspection apparatus including a detection unit that detects light from the subject is provided.

  According to the present invention, it is possible to scan a plurality of areas to be inspected at different depth positions substantially simultaneously.

1 is an overall configuration diagram of an optical scanning device according to a first embodiment of the present invention and a scanning inspection apparatus including the same. It is a figure explaining the relationship of the position of the focus of the beams irradiated to a sample in the scanning type inspection apparatus of FIG. It is a figure explaining the relationship between the position of the focus of the beam irradiated to a sample, and the scanning plane in the scanning type inspection apparatus of FIG. It is a figure explaining the modification of the positional relationship of the focus of the beams irradiated to a sample in the scanning type inspection apparatus of FIG. It is a figure explaining the modification of the relationship between the focus position of the beam irradiated to a sample, and the scanning plane in the scanning type inspection apparatus of FIG. It is a whole block diagram of the optical scanning device which concerns on the 2nd Embodiment of this invention, and a scanning type inspection apparatus provided with the same. It is a partial block diagram which shows the modification of the optical scanning device of FIG.

(First embodiment)
An optical scanning device 1 according to a first embodiment of the present invention and a scanning inspection apparatus 100 including the same will be described with reference to FIGS.

  As shown in FIG. 1, the optical scanning device 1 according to the present embodiment generates three beams L1 to L4 that travel in the same direction parallel to each other from a beam (laser light) L incident from a light source 12. Beam splitters 2a to 2c (parallelizing means) and mirrors (parallelizing means) 3, a first scanner (scanning unit) 4 that scans four beams L1 to L4, and each beam L1 to L4 is a first scanner. 4, a pair of lens systems (focusing position adjusting means) 5 that converges to 4, a slit 6 that limits a range through which each of the beams L 1 to L 4 scanned by the first scanner 4 passes, and a beam that has passed through the slit 6. The second scanner 7 that scans L1 to L4 in a direction orthogonal to the scanning direction of the first scanner 4 and the scanning timing of the beams L1 to L4 by the two scanners 4 and 7 are synchronized. And a part 8. In the figure, reference numeral 9 denotes a relay lens that relays the beams L1 to L4 that have passed through the slit 6, and reference numeral 10 denotes a pupil projection lens.

  The three beam splitters 2a to 2c are arranged in series on a predetermined optical axis A, and part of the beam L incident along the optical axis A is transmitted along the optical axis A and the other part is transmitted. The light is reflected in the same direction along the optical axes B1 to B3 perpendicular to the optical axis A. At this time, the ratio of the amount of light transmitted and reflected by the beam splitters 2a to 2c is set to 1: 3, 1: 2, and 1: 1 in order from the beam splitters 2a to 2c on the light source 12 side. Accordingly, four beams L1 to L4 having the same light amount are emitted from the three beam splitters 2a to 2c.

  The mirror 3 is disposed so as to reflect the beam L4 transmitted through the beam splitters 2a to 2c along the optical axis B4 and in the same direction as the reflection direction by the beam splitters 2a to 2c.

  Here, the optical axes B1 to B4 of the beams L1 to L4 reflected by the beam splitters 2a to 2c and the mirror 3 are arranged on the same plane. Further, the positions of the beam splitters 2a to 2c and the mirror 3 in the optical axis A direction are set so that the intervals between the optical axes B1 to B4 are substantially equal. As a result, four beams L1 to L4 traveling in parallel with each other at a substantially constant distance on the same plane are generated.

  The pair of lens systems 5 are provided between the beam splitters 2 a to 2 c and the mirror 3 and the first scanner 4. The pair of lens systems 5 includes movable lenses (converging lens systems) 51a to 51d disposed on the optical paths of the beams L1 to L4, and four beams L1 to L4 having a larger angle of view than the movable lenses 51a to 51d. And a collimating lens system (beam angle setting unit) 52 for commonly receiving light.

  The movable lenses 51a to 51d are converging lens systems that convert the beams L1 to L4 incident from the beam splitters 2a to 2c or the mirror 3 into convergent light beams. The movable lenses 51a to 51d are provided so as to be movable along the optical axes B1 to B4.

The collimating lens system 52 converts the beams L1 to L4, which are converged to the focal points F1 to F4 by the movable lenses 51a to 51d and then incident as diffused light beams, into substantially parallel light beams, emits them, and has optical axes parallel to each other. The four beams L1 to L4 incident along B1 to B4 are converged to one point.
In FIG. 1, the movable lenses 51 a to 51 d and the collimating lens system 52 are configured by a single lens, but these lens systems may be configured by a plurality of lenses.

  Here, the positions of the focal points F1 to F4 of the beams L1 to L4 between the movable lenses 51a to 51d and the collimating lens system 52 by moving the positions of the movable lenses 51a to 51d on the optical axes B1 to B4. Varies along the optical axes B1 to B4. In the present embodiment, as shown in FIG. 1, the optical axes B1 to B1 of the movable lenses 51a to 51d are arranged so that the positions of the four focal points F1 to F4 are closer to the collimating lens system 52 in order from the light source 12 side. A position on B4 is set. That is, when the movable lenses 51a to 51d have the same focal length, the movable lens 51a is arranged such that the distance between the movable lenses 51a to 51d and the collimating lens system 52 is gradually reduced from the light source 12 side. ˜51d are arranged on the optical axes B1 to B4.

  The first scanner 4 is composed of, for example, a galvanometer mirror, and is arranged at a position where the four beams L1 to L4 are converged by the collimating lens system 52. Thereby, the four beams L1 to L4 are given relative angles on the same plane and are collected at the same location in the first scanner 4. The first scanner 4 oscillates around an oscillation axis perpendicular to the plane common to the four beams L1 to L4, thereby causing the beams L1 to L4 incident at different angles on the plane to While maintaining the relative angles of the beams L1 to L4, scanning is performed in the arrangement direction of the beams L1 to L4.

  A converging lens (focusing optical system) 11 that receives the four beams L1 to L4 in common is provided at the subsequent stage of the first scanner 4. The converging lens 11 emits four beams L1 to L4 traveling in different directions from the first scanner 4 to the slit 6 in parallel with each other, and converts the beams L1 to L4 into convergent light beams. To form a focal point.

  The slit 6 has an opening 6a through which the beams L1 to L4 pass. The dimension of the opening 6a in the arrangement direction of the beams L1 to L4 is substantially the same as the interval between the adjacent beams L1 to L4. Thereby, only one of the four beams L1 to L4 passes through the slit 6 and the remaining three are blocked by the slit 6. As the first scanner 4 swings, the four beams L1 to L4 are emitted from the slit 6 in order.

The second scanner 7 oscillates around the oscillation axis perpendicular to the oscillation axis of the first scanner 4, thereby converting the beams L 1 to L 4 scanned by the first scanner 4 into the beams L 1 to L 4. Scan in a direction orthogonal to the array direction.
The control unit 8 changes the angle of the second scanner 7 relative to the swing axis by a predetermined angle every time the first scanner 4 swings one way.

Next, a scanning inspection apparatus 100 including the optical scanning apparatus 1 configured as described above will be described.
A scanning inspection apparatus 100 according to the present embodiment is a scanning microscope apparatus that scans beams L1 to L4 on a sample S to acquire an image of the sample S, and includes the optical scanning apparatus 1 and the optical scanning apparatus. 1 includes a light source 12 that makes a beam L incident along a predetermined optical axis A, a stage 13 on which a sample S is placed, and observation optics that irradiates the sample S with beams L1 to L4 scanned by the optical scanning device 1. The system 14, the detection unit 15 that detects the signal light generated in the sample S by the irradiation of the beams L1 to L4, and the restoration that restores the information of the signal light detected by the detection unit 15 as two-dimensional information or three-dimensional information And a display unit 17 for displaying the image information of the sample S restored by the restoration unit 16.

The observation optical system 14 includes an imaging lens 14a that images the beams L1 to L4 emitted from the pupil projection lens 10 of the optical scanning device 1, and the beams L1 to L4 that are imaged by the imaging lens 14a. And an objective lens 14b for irradiating the lens.
The restoration unit 16 receives information on the signal light detected by the detection unit 15 from the detection unit 15, receives information on the scanning positions of the beams L1 to L4 from the control unit 8, and converts the information on the signal light into the scanning position. Can be restored as two-dimensional information or three-dimensional information.

Next, operations of the optical scanning device 1 and the scanning inspection apparatus 100 will be described.
In order to acquire an image of the sample S by the scanning inspection apparatus 100 according to the present embodiment, a beam L is generated from the light source 12 and the beam L is incident on the optical scanning apparatus 1. In the optical scanning device 1, the beam L is divided into four so as to have substantially the same amount of light by three beam splitters 2a to 2c arranged in series. The divided four beams L1 to L4 are emitted in parallel to each other along the same plane from the beam splitters 2a to 2c and the mirror 3.

  The beams L1 to L4 are once returned to substantially collimated beams by the collimating lens system 52 after the focal points F1 to F4 are once formed at intermediate positions between the movable lenses 51a to 51d and the collimating lens system 52, respectively. The light is incident on the same position of the first scanner 4 at different angles by the lens system 52. The four beams L1 to L4 incident on the first scanner 4 are deflected by the first scanner 4 and incident on the converging lens 11, and are converted by the converging lens 11 so that their traveling directions are parallel to each other. 6 is incident.

  In the slit 6, the four beams L1 to L4 scanned by the first scanner 4 sequentially pass through the opening 6a one by one. The beam that has passed through the slit 6 passes through the relay lens 9, is deflected by the second scanner 7, is imaged by the imaging lens 14a via the pupil projection lens 10, and is irradiated onto the sample S by the objective lens 14b.

  Here, while the first scanner 4 swings one way once, the beams L1 to L4 passing through the slit 6 are switched in order. The four beams L1 to L4 are scanned one line at a time in the sample S. After the first scanner 4 swings one way once, the second scanner 7 swings by a predetermined angle, so that the positions where the beams L1 to L4 are next irradiated onto the sample S are perpendicular to the line. Move to. Thereby, in the sample S, the beams L1 to L4 are intermittently scanned two-dimensionally by the two scanners 4 and 7.

  By irradiating the sample S with the beams L <b> 1 to L <b> 4, signal light (for example, fluorescence) generated in the sample S passes through the stage 13 on which the sample S is placed and is detected by the detection unit 15. Information on the signal light detected by the detection unit 15 is restored as an image of the sample S in the restoration unit 16 and displayed on the display unit 17.

  In this case, according to the present embodiment, the positions of the focal points F1 to F4 of the beams L1 to L4 between the movable lenses 51a to 51d and the collimating lens system 52 are different from each other in the optical axis direction of the beams L1 to L4. Accordingly, as shown in FIG. 2, the positions of the focal points formed by the beams L1 to L4 converged by the converging lens 11 are also different from each other in the optical axis direction. As a result, the sample S is irradiated through the slit 6 The focal positions of the beams L1 to L4 are also different from each other in the depth direction (Z direction) of the sample.

  That is, as shown in FIG. 3, the four beams L1 to L4 are sequentially scanned on the planes P1 to P4 having different depth positions in the sample S. The difference in time at which the beams L1 to L4 are scanned on the planes P1 to P4 at this time is a sufficiently short time corresponding to the scanning period of the beams L1 to L4 by the first scanner 4. Therefore, four planes P1 to P4 having different depth positions of the sample S can be scanned and observed substantially simultaneously.

  In the present embodiment, the four beams P1 to P4 are observed by dividing the beam L from the light source 12 into four parts and making the focal positions of all the four beams L1 to L4 different from each other. However, the number of beams to be divided and the number of planes to be observed substantially simultaneously can be appropriately changed.

  For example, as shown in FIG. 4, the focal positions of the four beams L1 to L4 may be alternately changed between the two focal positions. At this time, every time the first scanner 4 swings halfway one way, the second scanner 7 swings by a predetermined angle. In this way, as shown in FIG. 5, two planes P1 and P2 having different depths can be observed almost simultaneously. At this time, the time required to scan the entire observation range is half as compared with the case of scanning one plane with one beam. In this way, the same plane P1 / P2 is divided into a plurality of beams L2, L4 / L1. By scanning using L3, the time required to acquire one image can be shortened.

(Second Embodiment)
Next, an optical scanning device 1 ′ according to a second embodiment of the present invention and a scanning inspection device 100 ′ including the same will be described with reference to FIGS. In the present embodiment, the configuration different from the optical scanning device 1 and the scanning inspection apparatus 100 according to the first embodiment will be mainly described, and the configuration common to the optical scanning apparatus 1 and the scanning inspection apparatus 100 is the same. The description is abbreviate | omitted and attached | subjected.

  As shown in FIG. 6, the optical scanning device 1 ′ according to the present embodiment includes means for generating a plurality of beams from the beam L output from the light source 12 and means for making the focal positions of the beams different from each other. This is mainly different from the first embodiment.

  That is, the optical scanning device 1 ′ includes a half-wave plate 21 on which the beam L is incident along the optical axis A from the light source 12, and the beam L transmitted through the half-wave plate 21 according to the polarization direction. A first polarizing beam splitter (branching unit) 22 that divides into two, and two pairs of mirrors (focusing position adjusting means) that fold back the two beams Lp and Ls divided by the first polarizing beam splitter 22 , Optical path length adjustment unit) 23, 24, a second polarization beam splitter (merging unit) 25 that merges the beams Lp, Ls folded by the mirror pairs 23, 24, and a halfway position between them. A pair of lens systems 5 ′ for connecting the focal points Fp and Fs to the beams Lp and Ls are provided.

In the present embodiment, the light source 12 outputs a beam L having linearly polarized light.
The half-wave plate 21 has an appropriate polarization direction in which the intensity of the two beams Lp and Ls separated by the first polarization beam splitter 22 is equal to the polarization direction of the beam L incident from the light source 12. Rotate to and emit.

  The first polarization beam splitter 22 separates the linearly polarized beam L emitted from the half-wave plate 21 by changing, transmits the beam Lp having P polarization along the optical axis A, and has S polarization. The beam Ls is emitted by being deflected by 90 ° along the optical axis B perpendicular to the optical axis A.

  The first mirror pair 23 includes two mirrors arranged to face each other at an angle of 90 °. One mirror is disposed on the optical axis A at an angle of 45 ° with the optical axis A, and reflects the beam Lp transmitted through the first polarizing beam splitter 22 by 90 °. The other mirror reflects the beam Lp reflected by the one mirror by 90 °, thereby folding the beam Lp along the optical axis A ′ parallel to the optical axis A.

  The second mirror pair 24 includes two mirrors arranged to face each other at an angle of 90 °. One mirror is disposed on the optical axis B at an angle of 45 ° with the optical axis B, and deflects the beam Ls reflected by the first polarizing beam splitter 22 by 90 °. The other mirror reflects the beam Ls reflected by the one mirror by 90 °, thereby folding the beam Ls along the optical axis B ′ parallel to the optical axis B.

  The second polarization beam splitter (parallelizing means) 25 transmits the beam Lp folded by the first mirror pair 23 along the optical axis A ′, and the beam Ls folded by the second mirror pair 24. By deflecting by 90 ° along the optical axis A ′, the two beams Lp and Ls are joined to the same optical path. The two beams Lp and Ls merged by the second polarization beam splitter 25 travel in parallel with each other along the optical axis A ′.

Here, the first mirror pair 23 and the second mirror pair 24 are provided so as to be movable in directions along the two optical axes A and B.
When the first mirror pair 23 moves in the direction along the optical axis A, the position of the focal point Fp of the beam Lp in the optical path moves in the optical axis direction of the beam Lp, and the second mirror pair 24 moves to the optical axis B. By moving in the direction along, the position of the focal point Fs of the beam Ls in the optical path moves in the optical axis direction of the beam Ls. In this way, by independently changing the optical path lengths of the two beams Lp and Ls in the subsequent stage of the first polarizing beam splitter 22, the positions of the focal points Fp and Fs of the beams Lp and Ls can be moved independently. it can.

  Further, by moving the first mirror pair 23 in the direction along the optical axis B, the beam Lp incident on the second polarization beam splitter 25 is translated in the direction intersecting the optical axis A ′, and the second By moving the mirror pair 24 in the direction along the optical axis A, the beam Ls incident on the second polarization beam splitter 25 is translated in the direction along the optical axis B ′. Thereby, only the distance interval between the two merged beams Lp and Ls can be changed.

  The pair of lens systems 5 ′ are arranged between the converging lens system 51 ′ disposed between the half-wave plate 21 and the first polarization beam splitter 22, and between the second polarization beam splitter 25 and the scanner 4. And a collimating lens system 52 ′ arranged.

  The converging lens system 51 ′ converts the beam L before being separated by the first polarization beam splitter 22 into a convergent light beam. Thereby, the optical path lengths of the two beams Lp and Ls separated by the first polarizing beam splitter 22 from the first polarizing beam splitter 22 to the positions of the focal points Fp and Fs are equal to each other.

  The collimating lens system 52 ′ receives in common the two beams Lp and Ls merged by the second polarization beam splitter 25, converts these beams L1 and L2 into substantially parallel light beams, emits them, and is parallel to each other. The two incident beams Lp and Ls are converged to one point.

  The scanning inspection apparatus 100 ′ including the optical scanning apparatus 1 ′ configured as described above is a scanning microscope apparatus that scans the beams Lp and Ls on the sample (subject) S and acquires an image of the sample S. In addition, the configuration other than the optical scanning device 1 ′ is the same as that of the scanning type inspection apparatus 100 of the first embodiment, and a description thereof will be omitted.

Next, the operation of the optical scanning device 1 ′ and the scanning inspection device 100 ′ will be described.
In order to acquire an image of the sample S by the scanning type inspection apparatus 100 ′ according to the present embodiment, a beam L is generated from the light source 12, and the beam L is incident on the optical scanning apparatus 1 ′ along the optical axis A. In the optical scanning device 1 ′, the polarization direction of the beam L is appropriately rotated by the half-wave plate 21, and then the converged light beam is transmitted through the converging lens system 51 ′. The first polarization beam splitter 22 is divided into two.

  The beam Lp having P-polarized light transmitted through the first polarizing beam splitter 22 is folded by the first mirror pair 23, and the beam Ls having S-polarized light reflected by the first polarizing beam splitter 22 is the second mirror. Folded by pair 24. Then, two beams Lp and Ls having different polarization directions are merged in the second polarization beam splitter 25. The two merged beams Lp and Ls go straight in parallel with each other.

  Here, these two beams Lp and Ls are once returned to a substantially collimated beam by the collimating lens system 52 ′ after the focal points Fp and Fs are once formed at a midway position between the converging lens system 51 ′ and the collimating lens system 52 ′. Then, the light is incident on the same position of the first scanner 4 at different angles by the collimating lens system 52 ′. The two beams Lp and Ls incident on the first scanner 4 are deflected by the first scanner 4 and incident on the converging lens 11. The converging lens 11 converts the traveling directions to be parallel to each other again. The light enters the slit 6.

  In the slit 6, the two beams Lp and Ls scanned by the first scanner 4 sequentially pass through the opening 6a one by one. The beam that has passed through the slit 6 passes through the relay lens 9, is deflected by the second scanner 7, is imaged by the imaging lens 14a via the pupil projection lens 10, and is irradiated onto the sample S by the objective lens 14b.

  Here, while the first scanner 4 swings one way once, the beams Lp and Ls passing through the slit 6 are switched in order. The two Lp and Ls are scanned one line at a time in the sample S. After the first scanner 4 swings one way once, the second scanner 7 swings by a predetermined angle, so that the position where the beam Lp, Ls is next irradiated on the sample S is perpendicular to the line. Move to. Accordingly, the beams Lp and Ls on the sample S are intermittently scanned two-dimensionally by the two scanners 4 and 7. Thereafter, an image of the sample S is generated in the same manner as in the first embodiment.

  In this case, according to the present embodiment, the positions of the focal points Fp and Fs of the Lp and Ls between the converging lens system 51 ′ and the collimating lens system 52 ′ are different from each other in the optical axis direction of the beams Lp and Ls. Accordingly, the positions of the focal points formed by the beams Lp and Ls converged by the converging lens 11 are also different from each other in the optical axis direction. As a result, the focal points of the beams Lp and Ls irradiated through the slit 6 to the sample S Are different from each other in the depth direction (Z direction) of the sample.

  That is, the two beams Lp and Ls are sequentially scanned on the sample S on the planes having different depth positions. The difference in time at which the beams Lp and Ls are scanned on each plane at this time is a sufficiently short time corresponding to the scanning period of the beams Lp and Ls by the first scanner 4. Therefore, two planes with different depth positions of the sample S can be scanned and observed substantially simultaneously.

  In the present embodiment, the beam L from the light source 12 is divided into two, and the focal positions of the two beams Lp and Ls are made different from each other in the optical axis direction, thereby observing two planes. However, the number of beams to be divided may be increased, and the number of planes to be observed substantially simultaneously and the number of beams used for scanning each plane may be appropriately changed.

  That is, as shown in FIG. 7, the optical scanning device 1 ′ includes a plurality of sets (two sets in the illustrated example) of the first group arranged in series between the converging lens system 51 ′ and the collimating lens system 52 ′. The polarizing beam splitter 22, the first mirror pair 23, the second mirror pair 24, and the second polarizing beam splitter 25 may be provided. Here, each beam that has passed through the first mirror pair 23 and the second mirror pair 24 in the preceding stage is converted into a group in the preceding stage and a group in the subsequent stage by a set of transmission lenses 27 denoted by reference numeral 27. Between the first mirror pair 23 and the second mirror pair 24, which are transmitted again as substantially parallel light beams. According to the configuration shown in FIG. 7, the beam L from the light source 12 can be divided into four. Reference numeral 26 denotes a mirror for deflecting the beam.

  In this way, by adjusting the positions of the first mirror pair 23 and the second mirror pair 24 in the preceding set and the first mirror pair 23 and the second mirror pair 24 in the subsequent stage, Similar to the embodiment, as shown in FIG. 2 or 4, the focal positions of the four beams on the sample S can be varied in the depth direction.

1, 1 'optical scanning device 100, 100' scanning type inspection device 2a-2c beam splitter (parallelizing means)
3 Mirror (parallelizing means)
4,7 Scanner (scanning part)
5,5 'pair of lens systems (focusing position adjustment means)
51a to 51d movable lens (focusing position adjusting means, converging lens system)
51 ′ Converging lens system 52, 52 ′ Collimating lens system (beam angle setting unit)
6 slit 6a aperture 8 control unit 9 relay lens 10 pupil projection lens 11 converging lens (focusing optical system)
DESCRIPTION OF SYMBOLS 12 Light source 13 Stage 14 Observation optical system 14a Imaging lens 14b Objective lens 15 Detection part 16 Restoration part 17 Display part 21 1/2 wavelength plate 22 1st polarizing beam splitter (branch part)
23, 24 Mirror pair (focus position adjustment means, optical path length adjustment unit)
25 Second polarization beam splitter (merging section, collimating means)
26 Mirror A Sample

Claims (15)

A beam angle setting unit that gives a plurality of laser beams traveling on the same plane to give a relative angle on the plane and collects the plurality of laser beams at the same place;
A scanning unit that scans the laser light gathered at the same location by the beam angle setting unit in a direction along the plane;
A focusing optical system that forms a focal point by converging each of the laser beams scanned by the scanning unit;
By adjusting the position of the focal point of each of the laser beams in the optical axis direction before Symbol laser beam formed by該合focusing optical system, the focus position to vary the position of at least a portion of the focal point on the optical axis An optical scanning device comprising adjustment means. Provided in series in front of the scanning unit, and having a pair of lens systems for emitting each laser beam to the scanning unit as a substantially parallel light beam after forming a focus on the plurality of laser beams at an intermediate position between them ,
The optical scanning device according to claim 1, wherein the focusing position adjusting unit adjusts a position of the focal point formed between the pair of lens systems in an optical axis direction of each laser beam. One of the pair of lens systems is a plurality of converging lens systems that are provided on an optical path of each laser beam and each laser beam is a convergent light beam,
The optical scanning device according to claim 2, wherein the focusing position adjusting unit adjusts a position in the optical axis direction in the optical path of each converging lens system.   The optical scanning device according to claim 3, wherein each of the converging lens systems is provided so as to be movable in an optical axis direction of each of the lasers. The optical scanning device according to claim 2, wherein the focusing position adjusting unit includes an optical path length adjusting unit that is provided between the pair of lens systems and adjusts an optical path length of each of the laser beams. Provided between the pair of lens systems, a branching unit that branches incident laser light into two optical paths, and a joining unit that joins the two optical paths branched by the branching unit into one,
The optical path length adjustment unit includes a pair of mirrors that are provided at an angle with each other in each optical path branched by the branching unit and that sequentially reflect the laser light incident from the branching unit and guide the laser beam to the joining unit. ,
The optical scanning device according to claim 5, wherein each of the pair of mirrors is capable of changing an optical path length from the branching portion to the merging portion via the pair of mirrors.   The optical scanning device according to claim 6, wherein the pair of mirrors are provided so as to be integrally movable in a direction along an incident optical axis of laser light incident from the branch portion.   8. The optical scanning device according to claim 6, wherein the pair of mirrors are provided so as to be integrally movable in a direction intersecting an incident optical axis of laser light incident from the branch portion.   The optical scanning device according to claim 6, wherein a plurality of sets of the branching unit, the pair of mirrors, and the merging unit are provided in series. Comprising a collimating means for mutually parallel optical axes of the plurality of laser beams in front of one of said pair of lens systems,
The other of the pair of lens systems receives the plurality of laser beams whose optical axes are parallel to each other by the collimating means, and collects the received laser beams at the same location. A collimating lens system,
The optical scanning device according to claim 2, wherein the beam angle setting unit includes the collimating lens system.   11. The optical scanning device according to claim 1, further comprising a slit that limits a range in a scanning direction through which the laser light scanned by the scanning unit passes.   The optical scanning device according to claim 1, further comprising another scanning unit that scans the laser light scanned by the scanning unit in a direction orthogonal to a scanning direction by the scanning unit. The in-focus position adjusting means has the same focal position in the optical axis direction of some of the plurality of laser beams,
The optical scanning device according to claim 12, wherein the another scanning unit scans the part of the plurality of laser beams to different positions in the orthogonal direction. 3. The optical scanning device according to claim 1, wherein the focus position adjusting unit makes the focal positions of the laser beams different from each other in an optical axis direction of the laser beams. An optical scanning device according to any one of claims 1 to 14 ,
An observation optical system for irradiating a subject with the laser beam scanned by the optical scanning device;
A scanning inspection apparatus comprising: a detection unit that detects light from the subject irradiated with the laser light by the observation optical system.

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