TWI722250B - Beam scanning device and pattern drawing device - Google Patents

Abstract

The drawing unit (Un) of the present invention is provided with a processing light beam (LBn) that deflects the reflective surface (RP) of a polygon mirror (PM) with a variable angle, and causes the processing light beam (LBn) to be focused on the substrate (P). The light is the fθ lens system (FT) of the spot light (SP), and the spot light (SP) is scanned according to the angle change of the reflecting surface (RP) of the polygon mirror (PM). The drawing unit (Un) is equipped with: a light beam transmitting part (60a), which projects the light beam (Bga) used to detect the origin of the polygon mirror (PM) as the origin of a predetermined angle (Bga) onto the polygon mirror (PM) The reflecting surface (RP); the reflecting mirror (MRa), which makes the light beam (Bgb) reflected on the reflecting surface (RP) incident and reflecting to the reflecting surface (RP); and the detection part (60b), which is based on the reflecting surface ( RP) The reflected beam (Bgd) again outputs the origin signal (SZn).

Description

Beam scanning device and pattern drawing device

The present invention relates to a beam scanning device that scans the spot light of a beam irradiated on an irradiated surface of an object, and a pattern drawing device that uses this beam scanning device to draw a predetermined pattern for exposure.

In the past, it has been known, for example, to use the laser processing device (optical scanning device) of Japanese Patent Laid-Open No. 2005-262260 as shown below to realize the following operation, that is, to project the spot light of the laser beam to the irradiated body (processing Object), and one side uses a scanning mirror (polygon mirror) to make the spot light perform main scanning in a one-dimensional direction, and the other side moves the illuminated object in the sub-scanning direction orthogonal to the main scanning direction to be illuminated The desired pattern or image (text, graphics, etc.) is formed on the body.

Japanese Patent Laid-Open No. 2005-262260 discloses the installation of the following components: a galvanometer mirror that reflects the laser light from the oscillator 1 and irradiates the laser light to the workpiece at the position where the laser light is irradiated on the workpiece Correction is performed in the Y direction (sub-scanning direction); a polygon mirror, which reflects the laser light reflected by the galvanometer mirror and makes it scan in the X direction (main scanning direction) on the workpiece; fθ lens, which makes The laser light reflected by the galvanometer mirror is condensed on the workpiece; and the control unit, which deals with the distortion aberration generated when the laser light passes through the fθ lens, to correct the Y-direction irradiation position of the laser light on the workpiece The error method controls the reflection angle of the galvanometer mirror, and the pulse oscillation interval of the laser light generated by the oscillator is controlled by the method of correcting the irradiation position error of the laser light on the workpiece in the X direction. Furthermore, Fig. 8 of Japanese Patent Application Laid-Open No. 2005-262260 shows a configuration in which a laser light source and a detector are set, and the pulse oscillation timing of the oscillator is controlled as shown in Fig. 9 based on the end detection signal. The light source emits detection laser light for detecting the end of each reflecting surface of the polygon mirror during the rotation of the polygon mirror. The detector receives the reflected light of the detection laser light reflected by the end of each reflecting surface of the polygon mirror and generates End detection signal.

Regarding the laser processing device (beam scanning device) using a polygon mirror as in Japanese Patent Laid-Open No. 2005-262260, the higher the rotation of the polygon mirror, the more the processing time of the processed object can be shortened. Improve productivity. On the other hand, the higher the rotation speed of the polygon mirror, the more obvious the deviation of the processing position in the main scanning direction.

The first aspect of the present invention is a beam scanning device, which is provided with a beam for processing which deflects the reflective surface of a scanning member with a variable angle to enter, and the beam for processing is focused on an irradiated body into a light spot A scanning optical system that scans the light spot at a scanning speed corresponding to the change in the angle of the reflection surface of the scanning member, and is equipped with a light beam transmission unit that detects that the reflection surface of the scanning member becomes a predetermined angle The light beam for detection at the origin is projected to the reflecting surface of the scanning member; a light beam reflecting portion that makes the light beam for detection reflected on the reflecting surface of the scanning member incident and reflected to the reflecting surface of the scanning member; and the light beam is received by the light beam. A portion that receives the reflected light beam of the detection light beam that is secondly reflected on the reflective surface of the scanning member, and outputs an origin signal indicating the origin.

The second aspect of the present invention is a pattern drawing device, which is provided with a scanning light beam that deflects the reflective surface of a scanning member whose angle is variable, and makes the drawing light beam incident on the substrate to be condensed into a light spot. The optical system is used to scan the light spot at a scanning speed corresponding to the angle change of the reflective surface of the scanning member, and the intensity of the drawing beam is adjusted according to the pattern, and the pattern is drawn on the substrate, and has ：Beam transmission part, which projects the detection beam used to detect the origin of the scanning member's reflection surface at a predetermined angle to the reflection surface of the scanning member; beam reflection part, which reflects on the reflection surface of the scanning member The detection light beam enters and is reflected to the reflecting surface of the scanning member; the light beam receiving part receives the reflected light beam of the detection light beam that is secondly reflected by the reflecting surface of the scanning member, and outputs the reflected light beam representing the origin An origin signal; and a control unit that controls the drawing of the pattern performed by the light spot based on the origin signal.

The third aspect of the present invention is a beam scanning device which uses a scanning optical system to condense a processing beam deflected by one of a plurality of reflecting surfaces of a rotating polygon mirror on an irradiated body into light The light spot is scanned by the rotation of the rotating polygon mirror, and it is equipped with: a light beam transmitting unit that detects each of the plurality of reflecting surfaces of the rotating polygon mirror as the origin of a predetermined angle The detection light beam is projected to the reflecting surface of the rotating polygon mirror; a beam reflecting portion that makes the detection light beam reflected on the reflecting surface of the rotating polygon mirror incident, and reflected to the reflecting surface of the rotating polygon mirror; and the light beam is received by the light beam. Section, which receives the reflected light beam of the detection light beam that is secondly reflected by the reflecting surface of the rotating polygon mirror, and outputs an origin signal indicating the origin.

60a‧‧‧Beam delivery part

60b‧‧‧Beam receiving part

A1, A2, Aw‧‧‧Arrow

AX1, AXf, AXj, AXv‧‧‧Optical axis

AXo‧‧‧Central axis

AXp‧‧‧Rotation axis

Bga‧‧‧Laser beam

Bgb, Bgb'‧‧‧reflected beam

Bgc, Bgc', Bgd, Bgd', LBn‧‧‧Beam

BS1‧‧‧Polarization beam splitter (first light splitting element)

BS2‧‧‧Polarization beam splitter (second light splitting element)

BSd‧‧‧Polarization beam splitter

CE, CE1‧‧‧Re-reflecting optical system

CMa、CMb‧‧‧Reflecting surface

CMw‧‧‧Corner mirror

CYa‧‧‧The first cylindrical lens

CYb‧‧‧The second cylindrical lens

DR‧‧‧Rotating drum

DTc‧‧‧Photodetector

DTo‧‧‧Photoelectric conversion element

EX‧‧‧Exposure device (pattern drawing device)

Fgs、fo‧‧‧focus distance

FT‧‧‧fθ lens system (scanning lens for drawing)

GLa‧‧‧Collimating lens

GLb, GLe‧‧‧lens system

GLc‧‧‧The first lens system

GLd‧‧‧Second lens system

IC1, IC2‧‧‧Current Amplifier

IC3‧‧‧Comparator section

IM1~IM6, IMn‧‧‧ incident mirror

LDo‧‧‧Semiconductor laser light source

Lpa, Lpb, Lpc, Lpd‧‧‧Main light

LS‧‧‧Light source device

M1~M12, M20~M24, M20a, M34, MRa, MRb, MRw‧‧‧Mirror

M33‧‧‧Mirror

Mcc‧‧‧Rotating fiducial mark

OS1~OS6, OSn‧‧‧Optical components for selection

P‧‧‧Substrate (irradiated body)

pb1, pb2‧‧‧polarization separation surface

PD1, PD2‧‧‧Light-receiving surface

PM‧‧‧Polygon mirror

QP1, QP2‧‧‧1/4 wavelength plate

RM‧‧‧Rotating Motor

RP、RPa~RPh‧‧‧Reflecting surface

SL1~SL6, SLn‧‧‧Drawing line

SP, SPr, SPr'‧‧‧point light

STa, STb‧‧‧output signal

SZn, SZn(a)1~SZn(a)7‧‧‧origin signal

TDa~TDh‧‧‧Rotation time

Tog, Tog1, Tog2‧‧‧origin time

TR‧‧‧Absorber

U1~U6, Un‧‧‧Drawing unit

Vh‧‧‧Speed

Vref‧‧‧Offset voltage (reference voltage)

X, Y, Z‧‧‧direction

△Te‧‧‧Tolerance

△Tm1~△Tm7、△Tma~△Tmh‧‧‧Origin interval time

△θe、θβ‧‧‧Angle

Fig. 1 is a perspective view showing a schematic configuration of an exposure device (pattern drawing device) that performs exposure processing on a substrate (irradiated body) of the first embodiment.

Fig. 2 is a diagram showing the optical structure of the drawing unit shown in Fig. 1.

Figure 3 is to observe the configuration of the polygon mirror in the drawing unit shown in Figure 2, the optical axis of the fθ lens system, and the beam transmitting part and the beam receiving part that constitute the origin sensor in a plane parallel to the XY plane. Get the picture.

Fig. 4 is a diagram showing the detailed structure of a photoelectric conversion element (photodetector) provided in the light beam receiving portion.

Fig. 5 is a diagram showing a beam transmitting part and a beam receiving part for reflecting the light beam for origin detection on the reflecting surface of the polygon mirror once, receiving the reflected light beam and outputting the origin signal.

Figure 6 is a top view of the 8-sided polygon mirror shown in Figures 1 to 3.

FIG. 7 is a diagram illustrating a method of measuring the reproducibility (deviation) of the origin signal generation timing.

FIG. 8 is a diagram schematically showing a method of predicting the amount of time error caused by the speed variation of the polygon mirror.

Fig. 9 is a graph showing the results obtained by measuring the reproducibility of the origin signal corresponding to each of the reflecting surfaces of the polygon mirror by using the methods shown in Figs. 7 and 8 under the established conditions.

Fig. 10 is a graph showing the results obtained by using the methods shown in Figs. 7 and 8 to measure the reproducibility of the origin signal generated corresponding to each of the reflecting surfaces of the polygon mirror under predetermined conditions different from Fig. 9 .

Fig. 11 is a diagram showing the structure of the origin sensor of the second embodiment.

Fig. 12 is a diagram showing the structure of the origin sensor of the third embodiment.

Fig. 13 is a schematic view obtained by observing the structure of Fig. 12 in a plane parallel to the XY plane.

Fig. 14 is a diagram showing the structure of the origin sensor of the fourth embodiment.

Fig. 15 is a diagram schematically showing the optical paths of the light beams in Fig. 14.

Fig. 16 is a diagram showing the structure of the origin sensor of the fifth embodiment.

Fig. 17 is a diagram showing a modification example of the structure of the origin sensor of the fifth embodiment.

Fig. 18 is a diagram showing the structure of the origin sensor of the sixth embodiment.

With regard to the beam scanning device and the pattern drawing device of the aspect of the present invention, preferred embodiments are given, referring to the accompanying drawings, and a detailed description is given below. Furthermore, the aspects of the present invention are not limited to these embodiments, and include those with various changes or improvements added. That is, the constituent elements described below include those that can be easily assumed by the manufacturer and those that are substantially the same, and the constituent elements described below can be appropriately combined. In addition, various omissions, substitutions, or changes of the constituent elements can be made without departing from the spirit of the present invention.

[First Embodiment]

FIG. 1 is a perspective view showing a schematic configuration of an exposure device (pattern drawing device) EX that performs exposure processing on a substrate (irradiated body) P of the first embodiment. Furthermore, in the following description, unless otherwise specified, an XYZ orthogonal coordinate system with the direction of gravity as the Z direction is set, and the X direction, Y direction, and Z direction are described according to the arrows shown in the figure.

The exposure apparatus EX is a substrate processing apparatus used in a component manufacturing system that performs predetermined processing (exposure processing, etc.) on the substrate P to manufacture electronic components. The device manufacturing system is, for example, a manufacturing system constructed with a production line for manufacturing flexible displays as electronic components, film-shaped touch panels, film-shaped color filters for liquid crystal display panels, flexible wiring, or soft sensors. Hereinafter, the description will be made on the premise of a flexible display as an electronic component. As flexible displays, there are, for example, organic EL displays, liquid crystal displays, and the like. The component manufacturing system has a so-called roll-to-roll (Roll To Roll) production method, that is, a supply roll (not shown) that rolls a soft (flexible) sheet substrate (sheet substrate) P into a roll. After the substrate P is sent out, and various treatments are continuously performed on the sent substrate P, the substrate P after various treatments is taken up by a recovery roller (not shown). Therefore, the substrate P after various treatments becomes a substrate for multiple chamfering in which a plurality of elements (display panels) are arranged in a state connected in the conveying direction of the substrate P. The substrate P conveyed from the supply roller passes through the processing device of the previous step, the exposure device EX, and the processing device of the subsequent step in order to be subjected to various processes, and is taken up by the recovery roller. The substrate P has a strip shape in which the moving direction (conveying direction) of the substrate P becomes the long side direction (long direction), and the width direction becomes the short side direction (short direction).

The substrate P uses, for example, a resin film, or a foil made of metal or alloy such as stainless steel. As the material of the resin film, for example, polyethylene resins, polypropylene resins, polyester resins, ethylene-vinyl ester copolymer resins, polyvinyl chloride resins, cellulose resins, polyamide resins, and polyimide resins can also be used. , At least one of polycarbonate resin, polystyrene resin, and vinyl acetate resin. In addition, the thickness or rigidity (Young's modulus) of the substrate P should be such that the substrate P does not produce creases or irreversible wrinkles caused by buckling when passing through the transport path of the component manufacturing system or the exposure device EX. can. As the base material of the substrate P, a film such as PET (polyethylene terephthalate) or PEN (polyethylene naphthalate) with a thickness of about 25 μm to 200 μm is representative of the preferred sheet substrate.

The substrate P is subject to heat during various processes implemented in the device manufacturing system, so it is preferable to select a substrate P made of a material with a low thermal expansion coefficient. For example, the thermal expansion coefficient can be suppressed by mixing an inorganic filler in the resin film. The inorganic filler may also be, for example, titanium oxide, zinc oxide, aluminum oxide, or silicon oxide. In addition, the substrate P may be a single layer body of ultra-thin glass with a thickness of about 100 μm manufactured by a float method or the like, or may be a laminate body formed by bonding the above-mentioned resin film, foil, etc., to the ultra-thin glass.

In addition, the so-called flexibility of the substrate P refers to the property that the substrate P can be bent without shearing or breaking even if a force of its own weight is applied to the substrate P. In addition, the nature of buckling due to the force of its own weight is also included in flexibility. In addition, the degree of flexibility varies depending on the material, size, thickness, layer structure of the film formed on the substrate P, temperature, humidity, and other environments. In short, as long as the substrate P is correctly wound around the various conveying rollers, rotating drums and other conveying direction switching members installed in the conveying path of the component manufacturing system (exposure apparatus EX), the substrate P can be wound without buckling. The smooth transfer of the substrate P with creases or breakages (cracks or cracks) can be referred to as the range of flexibility.

The process device of the previous step (including a single processing unit or a plurality of processing units) transports the substrate P sent from the supply roller toward the exposure device EX at a predetermined speed along the longitudinal direction, and the other side is transported to the exposure device EX The substrate P is processed in the previous step. Through the processing of this previous step, the substrate P conveyed to the exposure apparatus EX becomes a substrate (photosensitive substrate) on which a photosensitive functional layer (photosensitive layer) is formed.

This photosensitive functional layer becomes a layer (film) by coating on the substrate P in the form of a solution and drying. The representative of the photosensitive functional layer is photoresist (liquid or dry film), but as a material that does not require development processing, there are lyophilic/liquid-repellent modified photosensitive silane couples that are irradiated by ultraviolet rays Mixture (SAM), or a photosensitive reducing agent that exposes a plating reducing group on the part irradiated by ultraviolet rays. In the case of using a photosensitive silane coupling agent as the photosensitive functional layer, the pattern portion exposed to ultraviolet rays on the substrate P is transformed from liquid repellency to lyophilicity. Therefore, by selectively applying a liquid containing conductive ink (an ink containing conductive nanoparticles such as silver or copper) or a semiconductor material on the lyophilic part, it can be formed into a thin film transistor (TFT). Pattern layer for electrodes, semiconductors, insulation or wiring used for connection. When a photosensitive reducing agent is used as the photosensitive functional layer, the pattern portion exposed to ultraviolet rays on the substrate P reveals the plating reducing base. Therefore, after exposure, the substrate P is directly immersed in a plating solution containing palladium ions or the like for a fixed period of time, thereby forming (precipitating) a patterned layer of palladium. This plating process is an additive process, but in addition, it can also be used as a prerequisite for the etching process of a subtractive process. In this case, the substrate P sent to the exposure device EX is preferably made of PET or PEN as the base material, and a metallic thin film such as aluminum (Al) or copper (Cu) is deposited on the entire surface or selectively , And then laminated a photoresist layer on it.

Exposure device (processing device) EX is a process device (including a single processing section or multiple processing sections) that transports the substrate P transported from the process device of the previous step at a predetermined speed, and the substrate P is transported at the same time. Processing device for exposure processing. The exposure device EX irradiates the surface of the substrate P (the surface of the photosensitive functional layer, that is, the photosensitive surface) with a light pattern corresponding to the pattern for the electronic component (for example, the pattern of the electrode or wiring of the TFT constituting the electronic component). Thereby, a latent image (modified part) corresponding to the above-mentioned pattern is formed on the photosensitive functional layer.

In this embodiment, the exposure device EX is a direct-drawing method exposure device that does not use a mask as shown in FIG. 1, that is, a so-called spot scanning method exposure device (drawing device). The exposure device EX is equipped with: a rotating drum DR, which supports the substrate P for sub-scanning and conveys it in the longitudinal direction; and a plurality of (here, 6) drawing units Un (U1~U6), etc. Pattern exposure is performed on each part of the substrate P supported by the rotating drum DR in the shape of a cylindrical surface; each of the plurality of drawing units Un (U1~U6) uses a pulsed light beam LB (pulse beam) for exposure on one side The spot light SP is scanned one-dimensionally (main scanning) on the illuminated surface (photosensitive surface) of the substrate P in the predetermined scanning direction (Y direction) using a polygon mirror, and one side is based on the pattern data (drawing data, pattern information) High-speed modulation (on/off) of the intensity of the spot light SP. Thereby, a light pattern corresponding to a predetermined pattern of electronic components, circuits, wirings, etc., is drawn and exposed on the illuminated surface of the substrate P. That is, using the sub-scanning of the substrate P and the main scanning of the spot light SP, the spot light SP is relatively two-dimensionally scanned on the illuminated surface of the substrate P (the surface of the photosensitive functional layer), and the spot light SP is scanned on the illuminated surface of the substrate P. Describe the pattern of the exposure set. In addition, since the substrate P is transported in the longitudinal direction, the exposed regions of the pattern exposed by the exposure device EX are provided at a predetermined interval along the longitudinal direction of the substrate P and are provided in plural. Since electronic components are formed in the exposed area, the exposed area is also an element formation area.

As shown in FIG. 1, the rotating drum DR has a central axis AXo extending in the Y direction and extending in a direction intersecting the direction in which gravity acts, and a cylindrical outer peripheral surface having a fixed radius from the central axis AXo. The rotating drum DR supports (holds) a part of the substrate P in the shape of a cylindrical surface along the outer peripheral surface (circumferential surface) in the longitudinal direction, and rotates around the central axis AXo to extend the substrate P. Convey in the same direction. The rotating drum DR is supported by its outer peripheral surface on the area (part) on the substrate P on which the light beam LB (point light SP) from each of the plurality of drawing units Un (U1 to U6) is projected. The rotating drum DR supports (holds in close contact) the substrate P from the surface (back surface) opposite to the surface on which the electronic component is formed (the surface on which the photosensitive surface is formed). Furthermore, on both sides of the Y-direction of the rotating drum DR, there are provided shafts, not shown, supported by bearings in such a way that the rotating drum DR rotates around the central axis AXo. A rotation torque from a rotation driving source (for example, a motor or a deceleration mechanism, etc.) is applied to this shaft, and the rotating drum DR rotates at a fixed rotation speed around the central axis AXo.

The light source device LS generates and emits a pulse-shaped beam (pulse beam, pulse light, laser) LB. The light beam LB is ultraviolet light having sensitivity to the photosensitive layer of the substrate P and having a peak wavelength in the wavelength band below 370 nm. The light source device LS emits and emits a pulsed light beam LB at a frequency (oscillation frequency, predetermined frequency) Fa under the control of a drawing control device not shown in the text. The light source device LS is set as a fiber-amplified laser light source, which consists of a semiconductor laser element that generates pulsed light in the infrared wavelength region, an optical fiber amplifier, and converts the amplified pulsed light in the infrared wavelength region into pulsed light in the ultraviolet wavelength region The wavelength conversion element (harmonic generation element) and other components. By configuring the light source device LS in this way, high-intensity ultraviolet pulse light with an oscillation frequency Fa of several hundred MHz and a luminous time of one pulse light of tens of picoseconds or less can be obtained. Furthermore, the light beam LB emitted from the light source device LS becomes a relatively thin parallel light beam with a beam diameter of about 1 mm or less. Regarding the configuration that the light source device LS is set as a fiber-amplified laser light source and the pulse of the light beam LB is turned on/off at a high speed according to the state of the pixels constituting the drawing data (the logical value is "0" or "1") , Disclosed in the International Public Bulletin No. 2015/166910.

The light beam LB emitted from the light source device LS is selectively (selectively) supplied to each of the drawing units Un (U1~U6) through the beam switching part, which is used as a selection of a plurality of switching elements The optical element OSn (OS1~OS6), a plurality of reflecting mirrors M1~M12, a plurality of incident mirrors IMn (IM1~IM6), and an absorber TR are composed. The optical element OSn (OS1~OS6) for selection is transparent to the light beam LB, and is composed of an acousto-optic modulator (AOM: Acousto-Optic Modulator), which is driven by an ultrasonic signal to make the incident light The primary diffracted light of the light beam LB is emitted at a predetermined angle. The plural optical elements OSn for selection and the plural incident mirrors IMn are provided corresponding to each of the plural drawing units Un. For example, the selection optical element OS1 and the incident mirror IM1 are provided corresponding to the drawing unit U1, and similarly, the selection optical elements OS2 to OS6 and the incident mirror IM2 to IM6 are provided corresponding to the drawing units U2 to U6, respectively.

The light beam LB from the light source device LS is guided to the absorber TR by bending its optical path in a zigzag shape by the mirrors M1 to M12. Hereinafter, it will be described in detail when the optical elements OSn (OS1~OS6) for selection are all in an off state (a state where ultrasonic signals are not applied and no primary diffracted light is generated). In addition, although illustration is omitted in FIG. 1, a plurality of lenses are provided in the light beam path from the mirror M1 to the absorber TR. The plurality of lenses converge the light beam LB from the parallel light beam or diverge after converging. The beam LB is restored to a parallel beam. This structure will be explained using FIG. 4 below.

In FIG. 1, the light beam LB from the light source device LS travels in the -X direction parallel to the X axis and is incident on the mirror M1. The light beam LB reflected in the -Y direction by the mirror M1 is incident on the mirror M2. The light beam LB reflected in the +X direction by the mirror M2 directly passes through the selection optical element OS5 and reaches the mirror M3. The light beam LB reflected in the -Y direction by the mirror M3 is incident on the mirror M4. The light beam LB reflected in the -X direction by the mirror M4 directly passes through the selection optical element OS6 and reaches the mirror M5. The light beam LB reflected in the -Y direction by the mirror M5 is incident on the mirror M6. The light beam LB reflected in the +X direction by the mirror M6 directly passes through the selection optical element OS3 and reaches the mirror M7. The light beam LB reflected in the -Y direction by the mirror M7 is incident on the mirror M8. The light beam LB reflected in the -X direction by the mirror M8 directly passes through the selection optical element OS4 and reaches the mirror M9. The light beam LB reflected in the -Y direction by the mirror M9 is incident on the mirror M10. The light beam LB reflected in the +X direction by the mirror M10 directly passes through the selection optical element OS1 and reaches the mirror M11. The light beam LB reflected in the -Y direction by the mirror M11 is incident on the mirror M12. The light beam LB reflected in the -X direction by the mirror M12 directly passes through the selection optical element OS2 and is guided to the absorber TR. The absorber TR is a light trap that absorbs the light beam LB in order to suppress the leakage of the light beam LB to the outside.

Each optical element OSn for selection is a primary winding obtained by diffracting the incident light beam (zero-order light) LB at a diffraction angle corresponding to the high-frequency frequency when an ultrasonic signal (high-frequency signal) is applied. The emitted light is an emitted light beam (light beam LBn). Therefore, the light beam emitted from the optical element for selection OS1 as the primary diffracted light becomes LB1, and similarly, the light beam emitted from the optical element for selection OS2 to OS6 as the primary diffracted light becomes LB2 to LB6. In this way, each optical element OSn (OS1 to OS6) for selection functions to deflect the optical path of the light beam LB from the light source device LS. However, since the actual acousto-optic modulating element generates about 80% of the first-order diffracted light, the light beam LBn (LB1~LB6) deflected by selecting each of the optical elements OSn is better than the original one. The intensity of the light beam LB decreases. In addition, in the present embodiment, the selected one of the optical elements OSn (OS1 to OS6) for selection is controlled by a drawing control device not shown in such a way that the selected one is turned on only for a fixed time. When the one selected optical element OSn for selection is in the ON state, about 20% of the zero-order light traveling straight without being diffracted by the optical element OSn for selection remains about 20%, but it is eventually absorbed by the absorber TR.

Each of the optical elements OSn for selection is set in such a way that the light beams LBn (LB1 to LB6) as the deflected primary diffracted light are deflected in the -Z direction with respect to the incident light beam LB. The light beams LBn (LB1~LB6) deflected and emitted by each of the selection optical elements OSn are projected to the incident mirror IMn (IM1~IM6) which is provided at a position separated from each of the selection optical elements OSn by a predetermined distance. ). Each incident mirror IMn guides the light beam LBn (LB1~LB6) to the corresponding drawing unit Un (U1~U6) by reflecting the incident light beam LBn (LB1~LB6) in the -Z direction.

It is also possible to use those having the same configuration, function, and function of each optical element OSn for selection. Each of the plurality of optical elements OSn for selection is turned on/off according to the on/off of the driving signal (ultrasonic signal) from the drawing control device, which turns on/off the generated diffracted light that is diffracted by the incident light beam LB. For example, the optical element OS5 for selection transmits the incident light beam LB from the light source device LS without being diffracted when it is in an off state without applying a driving signal (high-frequency signal) from the drawing control device. Therefore, the light beam LB transmitted through the optical element OS5 for selection enters the mirror M3. On the other hand, when the optical element OS5 for selection is in the ON state, the incident light beam LB is diffracted and directed toward the incident mirror IM5. That is, the switching (beam selection) operation performed by the selection optical element OS5 is controlled based on the on/off of the drive signal. In this way, by the switching operation of each optical element OSn for selection, the light beam LB from the light source device LS can be guided to any drawing unit Un, and the drawing unit Un into which the light beam LBn is incident can be switched. In this way, regarding the configuration in which a plurality of optical elements OSn for selection are arranged in series (tandem) in order with respect to the light beam LB from the light source device LS, and the light beam LBn is supplied to the corresponding drawing unit Un in a time-sharing manner, it is disclosed in International Publication No. No. 2015/166910.

The order in which the optical elements OSn (OS1~OS6) for selection constituting the light beam switching unit are turned on at a fixed time is predetermined, for example, OS1→OS2→OS3→OS4→OS5→OS6→OS1→…. The sequence is determined according to the sequence of the start sequence of scanning with spot light set for each of the drawing units Un (U1~U6). That is, in this embodiment, the rotation speeds of the polygon mirrors provided in each of the six drawing units U1 to U6 are synchronized, and the phases of the rotation angles are also synchronized, whereby any one of the drawing units U1 to U6 is synchronized. One reflecting surface of the polygon mirror can be switched in a time-sharing manner by performing a spot scan on the substrate P once. Therefore, as long as the phases of the rotation angles of the polygon mirrors of the drawing unit Un are synchronized with a predetermined relationship, the order of the light spot scanning of the drawing unit Un can be arbitrary. In the configuration of FIG. 1, on the upstream side of the conveying direction of the substrate P (the direction in which the outer peripheral surface of the rotating drum DR moves in the circumferential direction), three drawing units U1, U3, and U5 are arranged side by side in the Y direction. On the downstream side of the conveyance direction of the substrate P, three drawing units U2, U4, and U6 are arranged side by side in the Y direction.

In this case, the pattern drawing on the substrate P starts from the odd-numbered drawing units U1, U3, U5 on the upstream side, and after the substrate P is transported for a fixed length, the even-numbered drawing units U2, U4, U6 on the downstream side The pattern drawing is also started, so the order of the light spot scanning of the drawing unit Un can be set as U1→U3→U5→U2→U4→U6→U1→... Therefore, the order in which each of the selection optical elements OSn (OS1 to OS6) is turned on at a fixed time is determined as OS1→OS3→OS5→OS2→OS4→OS6→OS1→.... Furthermore, even in the sequence in which the selection optical element OSn corresponding to the drawing unit Un that does not have a pattern to be drawn is turned on, the selection optical element OSn can be switched on/off based on the drawing data. By this control, it can be forcibly maintained in the off state, so that the light spot scanning using the drawing unit Un is not performed.

As shown in FIG. 1, each of the drawing units U1 to U6 is provided with a polygon mirror PM (scanning member) for main scanning of the incident light beams LB1 to LB6. In this embodiment, each of the polygon mirrors PM of each drawing unit Un is synchronously controlled in such a way that one side precisely rotates at the same rotation speed, and the other side maintains a fixed rotation angle phase with each other. Thereby, the main scanning timing of each of the light beams LB1 to LB6 projected from each of the drawing units U1 to U6 to the substrate P (the main scanning period of the spot light SP) can be set in a manner that does not overlap each other. Therefore, by synchronously controlling the on/off switching of each of the selection optical elements OSn (OS1~OS6) provided in the beam switching part with the rotation angle position of each of the 6 polygon mirrors PM, it can be realized An efficient exposure process for distributing the light beam LB from the light source device LS to each of the plurality of drawing units Un in a time-sharing manner.

The synchronization control of the phase alignment of the rotation angle of each of the 6 polygon mirrors PM and the on/off switching timing of each of the selection optical elements OSn (OS1~OS6) is disclosed in International Publication No. 2015 /166910, but in the case of 8-plane polygon mirror PM, as the scanning efficiency, about 1/3 of the rotation angle (45 degrees) corresponding to one reflecting surface corresponds to the point light SP on the drawing line SLn One scan, therefore, the switching of ON/OFF of each of the selection optical elements OSn (OS1~OS6) is controlled in the following way, that is, the 6 polygon mirrors PM are relatively shifted in the phase of the rotation angle by 15 The light beam LBn is scanned by rotating the 8 reflecting surfaces of each polygon mirror PM over one surface. In this way, the drawing method used to skip the reflective surface of the polygon mirror PM is also disclosed in International Publication No. 2015/166910.

As shown in FIG. 1, the exposure apparatus EX adopts a so-called multi-head type direct-drawing exposure method in which a plurality of drawing units Un (U1 to U6) of the same configuration are arranged. Each of the drawing units Un draws a pattern for each local area divided in the Y direction of the substrate P supported by the outer peripheral surface (circumferential surface) of the rotating drum DR. Each drawing unit Un (U1 to U6) projects the light beam LBn from the light beam switching unit onto the substrate P (the illuminated surface of the substrate P), and condenses (converges) the light beam LBn on the substrate P. Thereby, the light beam LBn (LB1 to LB6) projected on the substrate P becomes the spot light SP. In addition, by the rotation of the polygon mirror PM of each drawing unit Un, the spot light SP of the light beam LBn (LB1 to LB6) projected on the substrate P is scanned in the main scanning direction (Y direction). By the scanning of the spot light SP, a linear drawing line (scanning line) SLn (n=1, 2, ..., 6) for drawing a pattern of one line is defined on the substrate P. The drawing line SLn is also the scanning track on the substrate P of the spot light SP of the light beam LBn.

The drawing unit U1 scans the spot light SP along the drawing line SL1, and similarly, the drawing units U2 to U6 scan the spot light SP along the drawing lines SL2 to SL6. As shown in Figure 1, the drawing lines SLn (SL1~SL6) of the plurality of drawing units Un (U1~U6) are separated by the center plane including the central axis AXo of the rotating drum DR and parallel to the YZ plane, and are located on the center plane of the rotating drum DR. It is arranged in a staggered arrangement in two rows in the circumferential direction. The odd-numbered drawing lines SL1, SL3, SL5 are located on the irradiated surface of the substrate P on the upstream side (-X direction side) of the conveying direction of the substrate P with respect to the center surface, and are arranged at a predetermined interval along the Y direction Into 1 row. The even-numbered drawing lines SL2, SL4, SL6 are located on the irradiated surface of the substrate P on the downstream side (+X direction side) in the conveying direction of the substrate P with respect to the center surface, and are arranged at predetermined intervals along the Y direction Into 1 row. Therefore, a plurality of drawing units Un (U1 to U6) are also arranged in a staggered arrangement in two rows in the conveying direction of the substrate P across the center plane. If viewed in the XZ plane, the odd-numbered drawing units U1, U3, U5 The even-numbered drawing units U2, U4, U6 are arranged symmetrically with respect to the center plane.

It is set so that the odd-numbered drawing lines SL1, SL3, SL5 and the even-numbered drawing lines SL2, SL4, SL6 are separated from each other in the X direction (the transport direction of the substrate P), but in the Y direction (the width direction of the substrate P, the main In the scanning direction), they are joined without being separated from each other. The drawing lines SL1 to SL6 are substantially parallel to the width direction of the substrate P, that is, the central axis AXo of the rotating drum DR. In addition, joining the drawing line SLn in the Y direction means a relationship in which the positions of the ends of the drawing line SLn in the Y direction are adjacent to each other or partially overlapped. When the ends of the drawing lines SLn are overlapped with each other, for example, it is preferable to repeat the drawing start point or the drawing end point with respect to the length of each drawing line SLn by a few% or less in the Y direction.

In this way, the plurality of drawing units Un (U1 to U6) share the scanning area in the Y direction (division of the main scanning area) in a manner that all covers the size of the exposure area on the substrate P in the width direction. For example, if the main scanning range (length of the drawing line SLn) in the Y direction of one drawing unit Un is set to about 30-60 mm, a total of 6 drawing units U1 to U6 in the Y direction will be able to be drawn. The width of the exposure area in the Y direction is expanded to about 180~360mm. In addition, the length of each drawing line SLn (SL1 to SL6) (the length of the drawing range) is set to be the same in principle. That is, the scanning distance of the spot light SP of the light beam LBn scanning along each of the drawing lines SL1 to SL6 is set to be the same in principle.

In this embodiment, when the light beam LB from the light source device LS is pulsed light with a light emission time of tens of picoseconds or less, the spot light SP projected on the drawing line SLn during the main scanning period is based on the oscillation frequency Fa( For example, 400MHz) and discrete. Therefore, it is necessary to overlap the spot light SP projected by one pulse light of the light beam LB and the spot light SP projected by the next pulse light in the main scanning direction. The amount of overlap is set according to the size Φ of the spot light SP, the scanning speed of the spot light SP (the speed of the main scanning) Vs, and the oscillation frequency Fa of the light beam LB. When the intensity distribution of the spot light SP is approximated by a Gaussian distribution, the effective size (diameter) Φ of the spot light SP is determined by the width of the intensity that becomes ^{1/e 2 (or 1/2) of the peak intensity of the spot light SP} . In this embodiment, the scanning speed Vs (rotation speed of the polygon mirror PM) and the oscillation frequency Fa of the spot light SP are set such that the spot light SP overlaps Φ×1/2 with respect to the effective size (size) Φ. . Therefore, the projection interval of the pulse-shaped spot light SP along the main scanning direction becomes Φ/2. Therefore, it is preferable that in the sub-scanning direction (direction orthogonal to the drawing line SLn), the substrate P also moves the spot light SP between the first scan and the next scan of the spot light SP along the drawing line SLn The effective size Φ is approximately 1/2 of the distance. Furthermore, it is more desirable to also overlap Φ/2 when the drawing lines SLn adjacent in the Y direction are continuous in the main scanning direction. In this embodiment, the size (dimension) Φ of the spot light SP is set to approximately 3 to 4 μm.

Each drawing unit Un (U1~U6) is set in such a way that when viewed in the XZ plane, each light beam LBn travels toward the central axis AXo of the rotating drum DR. Thereby, the optical path of the light beam LBn (beam chief ray) traveling from each drawing unit Un (U1 to U6) toward the substrate P is parallel to the normal line of the illuminated surface of the substrate P on the XZ plane. In addition, the light beam LBn irradiated from each drawing unit Un (U1~U6) to the drawing line SLn (SL1~SL6) is always perpendicular to the cutting plane at the drawing line SLn of the surface of the substrate P curved in a cylindrical shape. Projected toward the substrate P. That is, in the main scanning direction of the spot light SP, the light beams LBn (LB1 to LB6) projected to the substrate P are scanned in a telecentric state.

The drawing unit (beam scanning device) Un shown in FIG. 1 has the same configuration, so only the drawing unit U1 will be briefly described. The detailed structure of the drawing unit U1 will be described below with reference to FIG. 2. The drawing unit U1 includes at least mirrors M20 to M24, a polygon mirror PM, and an fθ lens system (scanning lens for drawing) FT. Furthermore, in FIG. 1, although not shown, when viewed from the traveling direction of the light beam LB1, a first cylindrical lens CYa (refer to FIG. 2) is arranged in front of the polygon mirror PM, and a first cylindrical lens CYa (refer to FIG. 2) is arranged behind the fθ lens system FT. The second cylindrical lens CYb (refer to FIG. 2). The first cylindrical lens CYa and the second cylindrical lens CYb correct the positional change of the spot light SP (drawing line SL1) in the sub-scanning direction caused by the tilt error of each reflecting surface of the polygon mirror PM.

The light beam LB1 reflected by the incident mirror IM1 in the -Z direction is incident on the mirror M20 arranged in the drawing unit U1, and the light beam LB1 reflected by the mirror M20 travels in the -X direction and is incident on the mirror M21. The light beam LB1 reflected in the -Z direction by the mirror M21 enters the mirror M22, and the light beam LB1 reflected in the mirror M22 travels in the +X direction and enters the mirror M23. The reflecting mirror M23 reflects the incident light beam LB1 in a way that the reflecting surface RP of the polygon mirror PM is bent in a plane parallel to the XY plane.

The polygon mirror PM reflects the incident light beam LB1 toward the +X direction side of the fθ lens system FT. The polygon mirror PM scans the spot light SP of the light beam LB1 on the illuminated surface of the substrate P, and deflects (reflects) the incident light beam LB1 one-dimensionally in a plane parallel to the XY plane. Specifically, the polygon mirror (rotating polygon mirror, movable deflection member) PM has a rotation axis AXp extending in the Z-axis direction, and a plurality of reflection surfaces RP formed around the rotation axis AXp (in this embodiment, the reflection The number Np of the surface RP is set to 8) the rotating polygon mirror. By rotating the polygon mirror PM in a predetermined rotation direction with the rotation axis AXp as the center, the reflection angle of the pulse-shaped light beam LB1 irradiated on the reflecting surface can be continuously changed. Thereby, the light beam LB1 can be deflected by one reflecting surface RP, and the spot light SP of the light beam LB1 irradiated on the irradiated surface of the substrate P along the main scanning direction (the width direction of the substrate P, the Y direction) scanning. Therefore, in one rotation of the polygon mirror PM, the number of drawing lines SL1 scanned by the spot light SP on the illuminated surface of the substrate P is at most 8 the same as the number of the reflecting surface RP.

The fθ lens system (scanning system lens, scanning optical system) FT is a scanning lens of the telecentric system that projects the light beam LB1 reflected by the polygon mirror PM to the mirror M24. The light beam LB1 that has passed through the fθ lens system FT passes through the mirror M24 to become a spot light SP and is projected onto the substrate P. At this time, the mirror M24 reflects the light beam LB1 toward the substrate P in a manner that the light beam LB1 travels toward the central axis AXo of the rotating drum DR in the XZ plane. The incident angle θ of the light beam LB1 toward the fθ lens system FT changes according to the rotation angle (θ/2) of the polygon mirror PM. The fθ lens system FT transmits the mirror M24 to project the light beam LB1 to the image height position on the illuminated surface of the substrate P proportional to the incident angle θ. If the focal distance of the fθ lens system FT is set to fo and the image height position is set to yo, the fθ lens system FT is designed to satisfy the relationship of yo=fo×θ (distortion aberration). Therefore, the light beam LB1 can be accurately scanned in the Y direction at a uniform speed by the fθ lens system FT. Furthermore, the surface (parallel to the XY plane) to which the light beam LB1 incident to the fθ lens system FT is one-dimensionally deflected by the polygon mirror PM becomes a surface including the optical axis AXf of the fθ lens system FT.

Next, the optical configuration of the drawing unit Un (U1 to U6) will be described with reference to FIGS. 2 and 3. As shown in FIG. 2, in the drawing unit Un, a mirror M20, a mirror M20a, a polarization beam splitter BSd, and a mirror M20, a mirror M20a, a polarization beam splitter BSd, The reflecting mirror M21, the reflecting mirror M22, the first cylindrical lens CYa, the reflecting mirror M23, the polygon mirror PM, the fθ lens system FT, the reflecting mirror M24, and the second cylindrical lens CYb. Furthermore, in the drawing unit Un, in order to detect the drawing start timing of the drawing unit Un (the scanning start timing of the spot light SP), as shown in FIG. 3, the angular position of each reflecting surface of the detecting polygon mirror PM is provided. The origin sensor (origin detector) of the light beam transmitting part 60a and the light beam receiving part 60b (photodetector). The structure of the origin sensor (the beam transmitting part 60a and the beam receiving part 60b) will be described in detail below. In addition, a photodetector DTc is provided in the drawing unit Un. The photodetector DTc is used to detect the irradiated surface (or rotating drum) of the substrate P through the fθ lens system FT, the polygon mirror PM, and the polarization beam splitter BSd. The surface of the DR) the reflected light of the reflected light beam LBn.

The light beam LBn incident on the drawing unit Un travels in the -Z direction along the optical axis AX1 parallel to the Z axis, and is incident on the mirror M20 inclined by 45° with respect to the XY plane. The light beam LBn reflected by the mirror M20 moves toward the mirror M20a away from the mirror M20 in the -X direction and travels in the -X direction. The mirror M20a is arranged at an angle of 45° with respect to the YZ plane, and reflects the incident light beam LBn toward the polarization beam splitter BSd in the -Y direction. The polarization separation surface of the polarization beam splitter BSd is arranged at an angle of 45° with respect to the YZ plane, and reflects the P-polarized light beam and transmits the linearly polarized (S-polarized light) light beam that is polarized in the direction orthogonal to the P polarization. If the light beam LBn incident on the drawing unit Un is set as a P-polarized light beam, the polarization beam splitter BSd reflects the light beam LBn from the mirror M20a in the -X direction and guides it to the mirror M21 side. The mirror M21 is arranged at an angle of 45° with respect to the XY plane, and reflects the incident light beam LBn in the -Z direction toward the mirror M22 that is away from the mirror M21 in the -Z direction. The light beam LBn reflected by the mirror M21 is incident on the mirror M22. The mirror M22 is arranged at an angle of 45° with respect to the XY plane, and the incident light beam LBn is directed toward the mirror M23 and reflected in the +X direction. The light beam LBn reflected by the mirror M22 passes through the λ/4 wave plate and the cylindrical lens CYa (not shown), and is incident on the mirror M23. The mirror M23 reflects the incident light beam LBn to the polygon mirror PM.

The polygon mirror PM reflects the incident light beam LBn toward the fθ lens system FT having an optical axis AXf parallel to the X axis toward the +X direction side. The polygon mirror PM scans the spot light SP of the light beam LBn on the illuminated surface of the substrate P, and deflects (reflects) the incident light beam LBn one-dimensionally in a plane parallel to the XY plane. The polygon mirror PM has a plurality of reflecting surfaces (each side of the regular octagon in this embodiment) formed around the rotation axis AXp extending in the Z-axis direction, and is formed by the rotation motor RM coaxial with the rotation axis AXp Spin. The rotation motor RM is rotated at a fixed rotation speed (for example, about 30,000 to 40,000 rpm) by a drawing control device not shown. As explained above, the effective length (for example, 50mm) of the drawing lines SLn (SL1~SL6) is set to a length below the maximum scanning length (for example, 52mm) that can be scanned by the polygon mirror PM. In the initial setting (design), the center point of the drawing line SLn (the point through which the optical axis AXf of the fθ lens system FT passes) is set at the center of the maximum scanning length.

The cylindrical lens CYa converges the incident light beam LBn on the reflecting surface of the polygon mirror PM in the sub-scanning direction (Z direction) orthogonal to the main scanning direction (rotation direction) of the polygon mirror PM. That is, the cylindrical lens CYa converges the light beam LBn on the reflecting surface of the polygon mirror PM into a slit shape (oblong shape) extending in a direction parallel to the XY plane. With the cylindrical lens CYa whose generatrix is parallel to the Y direction and the cylindrical lens CYb described below, even when the reflecting surface of the polygon mirror PM is tilted from the state parallel to the Z axis, the substrate P can be prevented from being irradiated The irradiation position of the light beam LBn (drawing line SLn) on the irradiation surface is shifted in the sub-scanning direction.

字狀彎曲之光路彎折，且朝-Z方向行進並投射至基板P。一面使6個描繪單元U1~U6之各者將光束LB1~LB6之各點光SP於主掃描方向(Y方向)上一維地進行掃描，一面將基板P於長條方向上進行搬送，藉此，利用點光SP將基板P之被照射面相對地進行二維掃描，於基板P上使利用描繪線SL1~SL6之各者所描繪之圖案以於Y方向上接合之狀態曝光。 The incident angle θ of the light beam LBn toward the fθ lens system FT (the angle relative to the optical axis AXf) changes according to the rotation angle (θ/2) of the polygon mirror PM. When the incident angle θ of the light beam LBn toward the fθ lens system FT is 0 degrees, the light beam LBn incident on the fθ lens system FT travels along the optical axis AXf. The light beam LBn from the fθ lens system FT is reflected by the mirror M24 in the -Z direction, passes through the cylindrical lens CYb, and is projected toward the substrate P. With the fθ lens system FT and the cylindrical lens CYb whose generatrix is parallel to the Y direction, the light beam LBn projected to the substrate P converges on the illuminated surface of the substrate P into a tiny spot light with a diameter of about several μm (for example, 3~4 μm) SP. As described above, when viewed in the XZ plane, the light beam LBn incident on the drawing unit Un follows from the mirror M20 to the substrate P.

The curved light path in the shape of a letter is bent, travels in the -Z direction and is projected onto the substrate P. While allowing each of the six drawing units U1 to U6 to scan each spot light SP of the beams LB1 to LB6 one-dimensionally in the main scanning direction (Y direction), while conveying the substrate P in the longitudinal direction, Here, the illuminated surface of the substrate P is relatively scanned two-dimensionally by the spot light SP, and the pattern drawn by each of the drawing lines SL1 to SL6 is exposed on the substrate P in a state of being joined in the Y direction.

As an example, the effective scanning length LT of the drawing line SLn (SL1~SL6) is set to 50mm, the effective diameter Φ of the spot light SP is set to 4μm, and the oscillation frequency Fa of the pulse emission of the light beam LB from the light source device LS is set to For 400MHz, when the spot light SP is pulsed along the drawing line SLn (main scanning direction) in a manner that overlaps 1/2 of the diameter Φ each time, the pulse light emission of the spot light SP is separated from the substrate P in the main scanning direction The upper part becomes 2 μm, and this interval corresponds to the period Tf (=1/Fa) of the oscillation frequency Fa, that is, 2.5 nS (1/400 MHz). In this case, the pixel size Pxy specified on the drawing data is set to a 4 μm square on the substrate P, and one pixel is exposed with 2 pulses of the spot light SP in each of the main scanning direction and the sub scanning direction. Therefore, the scanning speed Vsp in the main scanning direction of the spot light SP and the oscillation frequency Fa are set to a relationship of Vsp=(Φ/2)/Tf. On the other hand, the scanning speed Vsp is based on the rotation speed VR (rpm) of the polygon mirror PM, the effective scanning length LT, the number of reflection surfaces of the polygon mirror PM Np (=8), and one reflection surface RP of the polygon mirror PM. The scanning efficiency 1/α is determined as follows.

Vsp=(8．α．VR．LT)/60[mm/sec]

Therefore, the oscillation frequency Fa and the rotation speed VR (rpm) are set in the following relationship.

(Φ/2)/Tf=(8．α．VR．LT)/60...Equation (1)

When the oscillation frequency Fa is set to 400 MHz (Tf=2.5nS) and the diameter Φ of the spot light SP is set to 4 μm, the scanning speed Vsp prescribed by the oscillation frequency Fa becomes 0.8 μm/nS (=2 μm/2.5nS). In order to cope with the scanning speed Vsp, when the scanning efficiency 1/α is set to 0.3 (α≒3.33) and the scanning length LT is set to 50mm, according to the relationship of formula (1), only the 8-sided polygon mirror PM The rotation speed VR can be set to 36000rpm. Furthermore, the scanning speed Vsp=0.8μm/nS in this case is 2880Km/h if converted to a speed per hour. In this way, if the scanning speed Vsp becomes high, it is necessary to improve the reproducibility of the origin signal generation timing from the origin sensor (the light beam transmitting portion 60a and the light beam receiving portion 60b) that determines the start timing of the drawing of the pattern. For example, when the size of 1 pixel is set to 4μm, and the minimum size (minimum line width) of the pattern to be drawn is set to 8μm (equivalent to the amount of 2 pixels), the pattern that has been formed on the substrate P is overlapped and exposed to a new The overlap accuracy (the allowable position error range) of the pattern during the second exposure must be set to about 1/4~1/5 of the minimum line width. That is, when the minimum line width is 8μm, the allowable range of position error becomes 2μm~1.6μm. This value is equal to or less than the interval of 2 pulses of the spot light SP corresponding to the oscillation period Tf (2.5 nS) of the light beam LB from the light source device LS, and means that the error of 1 pulse of the spot light SP is not allowed. Therefore, the reproducibility of the generation timing of the origin signal that determines the drawing start timing (start position) of the pattern must be set to the period Tf (2.5nS) or less.

Fig. 3 is to observe the polygon mirror PM in the drawing unit Un, the optical axis AXf of the fθ lens system FT, the beam transmitting part 60a and the beam receiving part 60b constituting the origin sensor in a plane parallel to the XY plane Figure obtained from configuration. In Fig. 3, the drawing beam LBn is projected toward one of the reflective surfaces RP of the polygon mirror PM, and the light beam LBn is projected toward one of the reflective surfaces RPa of the polygon mirror PM. The laser beam (beam for origin detection, beam for detection) Bga of the beam transmitting unit 60a. In addition, the angular position of the reflective surface RPa in FIG. 3 indicates a state where the point light SP of the drawing light beam LBn is located immediately before the drawing start point of the drawing line SLn. Here, the reflecting surface RP (RPa) of the polygon mirror PM is arranged so as to be located on the entrance pupil surface orthogonal to the optical axis AXf of the fθ lens system FT. Strictly speaking, the principal ray of the light beam LBn incident on the fθ lens system FT becomes the angular position of the reflective surface RP (RPa) at the moment when it is coaxial with the optical axis AXf, and the principal ray of the light beam LBn from the mirror M23 toward the polygon mirror PM The position where the light crosses the optical axis AXf sets the reflecting surface RP (RPa). In addition, the distance from the main surface of the fθ lens system FT to the surface of the substrate P (the condensing point of the spot light SP) is the focal distance fo.

The laser beam Bga from the beam transmitting portion 60a is projected to the reflective surface RPb of the polygon mirror PM as a parallel beam of a wavelength region that is non-photosensitive to the photosensitive functional layer of the substrate P. The reflected beam Bgb of the laser beam Bga reflected on the reflective surface RPb faces the mirror (beam reflection part) MRa having a reflective surface perpendicular to the XY plane. The reflected light beam Bgc of the light beam Bgb reflected by the mirror MRa is again projected toward the reflection surface RPb of the polygon mirror PM. The reflected light beam Bgd of the light beam Bgc reflected on the reflective surface RPb is received by the light beam receiving portion 60b. The light beam receiving portion 60b is located at the moment when the reflecting surface RPb (and other reflecting surfaces RP) of the polygon mirror PM becomes a specific angular position in the plane parallel to the XY plane (XY plane), so that the light beams Bga, Bgb, Bgc, Bgd As shown in Fig. 3, the light beam receiving unit 60b outputs an origin signal SZn that changes in a pulse shape. In FIG. 3, the light beam Bga is simply expressed as a line, but in fact, in order to make it a parallel light beam having a predetermined width in the XY plane in the rotation direction of the reflecting surface RP of the polygon mirror PM, the light beam transmitting section 60a With semiconductor laser light source and collimating lens. Similarly, in Fig. 3, the light beam Bgd is simply expressed as a line, but actually becomes a parallel light beam having a predetermined width in the XY plane. The light beam Bgd responds to the rotation of the polygon mirror PM and responds to the light beam receiving portion 60b as an arrow Aw Normally scan. Therefore, the light beam receiving portion 60b has: a photoelectric conversion element, which outputs the origin signal SZn when receiving the light beam Bgd; and a condenser lens, which condenses the light beam Bgd on the light receiving surface of the photoelectric conversion element into a light spot.

Fig. 4 shows the detailed structure of the photoelectric conversion element (photodetector) DTo provided in the light beam receiving portion 60b. In this embodiment, for example, S9684 manufactured by Hamamatsu Photonics Co., Ltd. is used as a photoelectric IC for laser beam synchronization detection. series. This photo-IC is the light receiving of two PIN photodiodes arranged in the scanning direction of the spot light SPr of the beam Bgd collected by the condensing lens as shown in Figure 4 with a narrow gap (non-sensitive band). The surface PD1, PD2, the current amplifying parts IC1, IC2, and the comparator part IC3 are packaged as a single unit. If the light beam Bgd is scanned like the arrow Aw shown in FIG. 3, the spot light SPr traverses in the order of the light-receiving surfaces PD1 and PD2, and each of the current amplifying parts IC1 and IC2 generates as shown in FIG. 4(A) The output signal STa, STb. A fixed offset voltage (reference voltage) Vref is applied to the current amplifying part IC1 that amplifies the photocurrent from the light-receiving surface PD1 that first receives the spot light SPr, so that the output signal STa of the current amplifying part IC1 is the light generated on the light-receiving surface PD1 When the current is zero, the bias voltage becomes the reference voltage Vref. As shown in Figure 4(B), the comparator IC3 compares the levels of the output signals STa and STb, and outputs the logic signal that becomes the H level when STa>STb and becomes L when STa<STb is the origin. Signal SZn. In this embodiment, the time point when the origin signal SZn changes from the H level to the L level is the origin time (origin position) Tog, and the so-called generation timing of the origin signal SZn means the origin time Tog. In addition, the origin position (origin time Tog) here does not mean that when the point on the substrate P through which the optical axis AXf of the fθ lens system FT passes is set as the reference point, it is taken as the reference point In the main scanning direction of the spot light SP, it is always set at a fixed distance to the origin of the immediate absolute position, and it represents relatively before a predetermined distance (or before a predetermined time) with respect to the start timing of the pattern drawing along the drawing line SLn )By.

The origin time Tog becomes the moment when the levels of the output signals STa and STb coincide in the middle of the decrease of the level of the output signal STa and the increase of the level of the output signal STb. The level change of the output signal STa, STb (rising or falling waveform) can be based on the relationship between the width of the light receiving surface PD1, PD2 and the size of the spot light SPr, the scanning speed Vh of the spot light SPr and the response of the light receiving surface PD1, PD2 However, as long as the diameter of the spot light SPr is larger than the width of the non-sensitive band and smaller than the width of the light-receiving surface PD1, each of the output signals STa and STb becomes the result of using level changes as shown in Figure 4(A) The waveform can obtain a stable origin signal SZn.

In the present embodiment, as shown in FIG. 3, it is configured as follows: the light beam Bga for origin detection is reflected twice on the reflecting surface RP (RPb) of the polygon mirror PM using the photoelectric conversion element DTo to receive the mirror MRa. Spot light SP of light beam Bgd. Therefore, the scanning speed Vh of the spot light SPr on the light-receiving surfaces PD1 and PD2 can be made comparable to the case where the origin detection light beam Bga is reflected once on the reflecting surface RP (RPb) of the polygon mirror PM and received by the photoelectric conversion element DTo. The ratio becomes more than twice. Accordingly, in this embodiment, compared with the scanning speed Vsp on the substrate P of the drawing beam LBn (spot light SP), the origin detection beam Bgd (spot light SPr) on the photoelectric conversion element DTo can be The scanning speed Vh is accelerated by about twice, and the reproducibility of the generation timing of the origin signal SZn can be improved (the 3σ value representing the distribution range of the deviation is reduced).

Therefore, as shown in FIG. 5, a configuration in which the photoelectric conversion element DTo of the light beam receiving portion 60b receives the reflected light beam Bgb obtained by reflecting the origin detection light beam Bga on the reflecting surface RP (RPb) of the polygon mirror PM once is used. When the scanning speed Vsp of the spot light SP of the drawing light beam LBn is the same as the scanning speed Vh of the spot light SPr of the origin detection light beam Bgb, the scanning speed Vh of the spot light SPr is relative to the scanning speed Vsp of the spot light SP When the speed is about 2 times, try to compare the reproducibility of the origin signal SZn.

In FIG. 5, the light beam sending unit 60a includes: a semiconductor laser light source LDo, which continuously emits a laser beam Bga; and a collimator lens GLa (the first optical element with refractive power), which makes the light beam Bga from the light source Become a parallel beam. The light beam Bga is a parallel light beam having a certain width in the rotation direction of the reflecting surface RP (RPb) (the main scanning direction parallel to the XY plane). On the other hand, in the light beam receiving portion 60b, a lens is provided for condensing the reflected light beam Bgb on the photoelectric conversion element DTo which is the same as that in FIG. System GLb (the second optical element with refractive power). The light-receiving surfaces PD1 and PD2 of the photoelectric conversion element DTo shown in FIG. 4 are arranged at the position of the focal distance Fgs behind the lens system GLb. It is set so that when the reflected light beam Bgb reflected on the reflective surface RP (RPb) is incident coaxially with the optical axis of the lens system GLb, the spot light SPr of the reflected light beam Bgb is located approximately in the center of the light-receiving surface of the photoelectric conversion element DTo (light-receiving surface PD1, No sense zone between PD2). Furthermore, the light beam receiving portion 60b is constituted by the photoelectric conversion element DTo and the lens system GLb to form a detection portion for generating the origin signal SZn.

Even when the reflected light beam Bgb' which is slightly inclined in the main scanning direction with respect to the optical axis of the lens system GLb is incident, the reflected light beam Bgb' becomes a spot light SPr and focuses on the same surface as the light-receiving surface of the photoelectric conversion element DTo Inside. The reflected light beam Bgb′ from the lens system GLb toward the photoelectric conversion element DTo does not need to be telecentric. In the above configuration, if the focal distance Fgs of the lens system GLb is made the same as the focal distance fo of the fθ lens system FT, the scanning speed Vsp of the point light SP of the drawing beam LBn and the point of the origin detection beam Bgb The scanning speed Vh of the light SPr is approximately the same. In addition, if the focal distance Fgs of the lens system GLb is set to be approximately twice the focal distance fo of the fθ lens system FT, the scanning speed Vh of the spot light SPr of the origin detection light beam Bgb is relative to the point light of the drawing light beam LBn The scanning speed Vsp of SP is accelerated by about 2 times.

Next, referring to FIGS. 6-8, the method of measuring and calculating the reproducibility (deviation error) of the generation timing of the origin signal SZn from the origin sensor constructed in the manner of FIG. 5 will be described. The measurement or calculation can be performed by a computer that controls the exposure device EX as a whole, or controls the rotation of the polygon mirror PM for pattern drawing, the pulse oscillation of the light beam LB from the light source device LS corresponding to the drawing data, and the optical elements OS1~OS6 for selection. The switching, etc., is implemented by the processor (CPU) of the drawing control device, etc. Moreover, it can also be implemented by sending the origin signal SZn to an external waveform measuring device or the like. Fig. 6 is a plan view of the 8-sided polygon mirror PM shown in Figs. 1 to 3. Here, the reproducibility of the origin signal SZn generated as shown in Fig. 4(B) is obtained for each of the 8 reflecting surfaces RP Therefore, the rotation direction (clockwise) of the eight reflecting surfaces RP and the polygon mirror PM can be reversed to RPa, RPb, RPc, RPd, RPe, RPf, RPg, RPh. In addition, on the upper surface (or lower surface) of the polygon mirror PM, a rotation reference mark Mcc useful for detecting the origin of the rotation of the polygon mirror PM is formed. The rotation reference mark Mcc is detected by a reflection type photoelectric sensor (also called a rotation detection sensor) that outputs a pulse-shaped detection signal every time the polygon mirror PM rotates one turn. When measuring the reproducibility of the origin signal SZn, the reflecting surface of the polygon mirror PM detected by the origin sensor must be specified. Therefore, the detection signal from the rotation detection sensor (rotation reference mark Mcc) is used as the reference to specify Each reflecting surface RPa~RPh of the polygon mirror PM is shown.

Furthermore, when measuring the reproducibility of the generation timing of the origin signal SZn, the influence caused by the speed variation (speed unevenness) of the polygon mirror PM must be considered. The speed variation of the polygon mirror PM can also be measured by the above-mentioned rotation detection sensor, but in this embodiment, the speed variation of the polygon mirror PM is measured based on the origin signal SZn. As exemplified above, if the motor RM of the polygon mirror PM is set to rotate at 36000 rpm and the drawing control device is used for servo control, the polygon mirror PM will rotate 600 times in 1 second, which is designed to rotate 1 turn The rotation time TD becomes 1/600 second (≒1666.667μS). Therefore, a clock pulse with a higher frequency than the oscillation frequency Fa of the light source device LS for pulsed light emission is used to repeatedly measure the origin time Tog of any pulse in the origin signal SZn and count to the origin of the 9th pulse. The actual rotation time TD until the time Tog. The polygon mirror PM rotates at a high speed with inertia, so the possibility of uneven speed during one rotation is low. According to the characteristics of the servo control, there is a design rotation time within a period of several mS to tens of mS. The situation where the TD changes subtly.

FIG. 7 is a diagram illustrating a method of measuring the reproducibility (deviation) of the generation timing of the origin signal SZn. Here, in order to simplify the description, an example of the method of seeking the reproducibility of the origin time Tog2 of the origin signal SZn generated corresponding to the reflecting surface RPa of the polygon mirror PM shown in FIG. 6 is shown for each of the other reflecting surfaces RPb~RPh. The same can also be done for measurement. In the case of FIG. 6, the origin time Tog1 generated one time sequence before the origin time Tog2 can be obtained as the origin signal SZn generated corresponding to the reflecting surface RPh of the polygon mirror PM. Therefore, in the state that the polygon mirror PM is rotated at a predetermined speed, the polygon mirror PM repeats the measurement multiple times (for example, more than 10 times) every time the polygon mirror PM rotates one revolution from the origin time Tog1 generated corresponding to the reflecting surface RPh to the corresponding The origin interval time △Tmn (the number of rotations of n=1, 2, 3...) to the origin time Tog2 of the next reflecting surface RPa. In FIG. 7, to simplify the description, the origin time Tog1 obtained corresponding to the reflecting surface RPh is aligned on the time axis to represent the origin signal SZn( a) The waveform of each of 1~SZn(a)7.

Here, if it is assumed that the variation of the rotation speed of the polygon mirror PM is zero, the measured value of each of the original interval time ΔTmn, which should have been fixed, will deviate. This deviation becomes the deviation amount △Te of the generation sequence of the origin time Tog2 corresponding to the reflecting surface RPa, and the reproducibility of the origin signal SZn is set as the standard deviation value of the plural origin time Tog2 distributed within the deviation amount △Te σ, or a 3σ value that is three times the standard deviation value σ. As explained above, when the light source device LS pulses the light beam LB with the period Tf, the 3σ value as the reproducibility is preferably smaller than the period Tf. In the above description, although the rotation speed variation (speed unevenness) of the polygon mirror PM is assumed to be zero, if a waveform tester that samples the signal waveform with a resolution below nanoseconds is used to analyze the origin signal SZn And try to measure the rotation time of the polygon mirror PM (the time of one rotation), and it is judged that the rotation time TD varies by ± nS due to the rotation. Therefore, the origin interval time ΔTmn (the number of rotations for n=1, 2, 3...) measured in the manner shown in Fig. 7 must be corresponded to the polygon mirror PM during the measurement period due to the origin interval time ΔTmn The amount of error caused by the speed change is corrected.

FIG. 8 is a diagram schematically showing a method of predicting the amount of time error caused by the speed variation of the polygon mirror PM. In the measurement of the reproducibility of the origin signal SZn from the origin sensor shown in Fig. 5, for each of the multiple rotations of the polygon mirror PM, the measurement corresponds to each of the 8 reflecting surfaces RPa~RPh The origin interval time △Tmn. In FIG. 8, it is schematically shown that the initial position (initial origin time Tog) in one rotation of the polygon mirror PM is set to the reflective surface RPa, and the polygon mirror PM is generated within the period of 2 rotations from the reflective surface RPa. The waveform of the origin signal SZn. Here, the origin time interval from the origin time Tog generated by the reflection surface RPa corresponding to the origin signal SZn to the origin time Tog generated corresponding to the adjacent reflection surface RPb is set as △Tma, the following In the same way, the origin interval time from the adjacent reflecting surface RPb to the reflecting surface RPc is set to △Tmb..., the origin interval from the adjacent reflecting surface RPh to the reflecting surface RPa The time is set to △Tmh. In the first week of the polygon mirror PM, set each origin time Tog corresponding to each of the 8 reflecting surfaces RPa~RPh as the starting point, and measure each of the reflecting surfaces RPa~RPh of the polygon mirror PM The rotation time TDa, TDb,...TDh. Each of the rotation time TDa~TDh can also be calculated by the total value of the 8 origin interval time △Tma~△Tmh corresponding to each of the 8 reflecting surfaces RPa~RPh. Each of the rotation time TDa ~ TDh (or the origin interval time △Tma ~ △Tmh) is repeatedly measured during the period of N rotation of the polygon mirror PM, for example. Thereby, the data of each of the rotation time TDa~TDh counted from the origin time Tog corresponding to each of the 8 reflecting surfaces RPa~RPh can be obtained continuously for N revolutions.

Secondly, calculate the average rotation time ave(TDa)~ave(TDh) of each of the rotation times TDa~TDh obtained for N cycles. For example, the rotation time TDa corresponds to the number of rotations N (N=1, 2, 3...) and is memorized as TDa(1), TDa(2), TDa(3),...TDa(N), so the average rotation time ave (TDa) can be calculated using [TDa(1)+TDa(2)+TDa(3)+,...+TDa(N)]/N.

Secondly, suppose that each of the origin interval time △Tma~△Tmh measured after the second circle shown in Fig. 8 includes the error caused by the influence of the speed change of the previous polygon mirror PM, for example, regarding the first The measured interval time between the origins △Tma after 2 laps, the prediction is only based on the ratio of the measured rotation time TDa and the average rotation time ave(TDa) in the previous rotation, and the predicted interval time △Tma of the initial interval time △Tma is calculated. Tma'. At this time, find the average interval time ave (ΔTma) of the N-1 origin interval time ΔTma measured in each rotation after the second turn. Then, the ratio of the average rotation time ave (TDa) to the measured rotation time TDa is multiplied by the average interval time ave (ΔTma) to calculate the predicted interval time ΔTma' after the amount of speed variation is corrected. Thereby, the difference between the measured origin interval time ΔTma and the predicted interval time ΔTma' is set to correspond to the more accurate deviation of the origin time Tog of the origin signal SZn generated by the reflecting surface RPa ( σ value). The deviation amount of the origin time Tog of the origin signal SZn corresponding to each of the other reflecting surfaces RPb~RPh is also calculated by the same calculation. In this way, only by repeating the generation interval of the origin time Tog of the actual measured origin signal SZn during the multiple rotations of the polygon mirror PM, that is, the origin interval time △Tma~△Tmh, the use of the polygon mirror PM can be obtained. Accurate reproducibility (3σ value, etc.) of the error reduction caused by the speed change.

[Measured example]

As an example, the focal distance Fgs of the lens system GLb in the light beam receiving portion 60b shown in FIG. 5 is set to be the same as the focal distance fo (for example, 100 mm) of the fθ lens system FT, and the photoelectric conversion element DTo is arranged in the lens system GLb The position of the focal point distance Fgs makes the polygon mirror PM rotate at about 38000 rpm, and the origin signal SZn (original point signal SZn) generated corresponding to each of the reflecting surfaces RPa~RPh of the polygon mirror PM is measured by the method shown in Figure 7 and Figure 8. After clicking the reproducibility at time Tog2), the result shown in Figure 9 can be obtained. In Figure 9, the horizontal axis represents the positions between the measured reflecting surfaces (RPa→RPb, RPb→RPc,...RPh→RPa), and the vertical axis represents the positions between the reflecting surfaces after the change in the rotation time TD is corrected and calculated. The interval time between △Tma~△Tmh(μS). The interval time △Tma~△Tmh is to use a waveform memory device with a sampling frequency of 2.5GHz (0.4nS) to memorize the waveform data of the origin signal SZn generated continuously during 10 rotations of the polygon mirror PM, and perform processing on the waveform data. Analysis and actual measurement.

As shown in Figure 9, the interval time △Tma~△Tmh after correcting the variation of the rotation time TD has a deviation between 197.380μS~197.355μS. When the polygon mirror PM rotates precisely at a rotation speed of 38000 rpm, the calculated interval time △Tma~△Tmh is 197.368μS. The deviation of this interval time △Tma~△Tmh, for example, is due to the fact that each of the 8 vertex angles formed by the adjacent reflective surfaces of the polygonal mirror PM's reflective surfaces RPa~RPh does not accurately become 135 degrees, or self The distance from the rotation axis AXp to each of the reflective surfaces RPa to RPh does not precisely become a shape error in processing such as fixation. Moreover, the deviation of the interval time △Tma~△Tmh will also be generated according to the degree of the eccentricity error of the polygon mirror PM with respect to the rotation axis AXp. In Fig. 9, the 3σ value calculated from the distribution of the deviation of each of the interval time △Tma~△Tmh becomes 2.3nS~5.9nS, but this value means that the pulse oscillation frequency of the light beam LB from the light source device LS When set to 400MHz (period 2.5nS), the error of the scanning position of the spot light of approximately 3 pulses or more can be generated. As exemplified above, when the diameter Φ of the spot light SP is set to 4 μm, the size of 1 pixel Pxy is set to 4 μm square on the substrate P, and the amount of 1 pixel is drawn with 2 pulses of the spot light SP, if 3σ The value is about 6nS, which means that the position of the pattern drawn along the drawing line SLn has a deviation of about 5 μm (to be precise, 4.8 μm) in the main scanning direction.

When the focal distance of the fθ lens system FT is set to fo, and the pulse interval distance of the spot light SP on the substrate P (1/2 of the spot diameter) is set to △Yp, it corresponds to the multi-faceted pulse interval distance △Yp The angle change Δθp of the mirror PM (reflecting surface) becomes Δθp≒ΔYp/fo. On the other hand, if the moving distance of the laser beam Bgb (spot light SPr) on the photoelectric conversion element DTo corresponding to the angle change △θp is set to △Yg, the focal distance of the lens system GLb on the side of the beam receiving unit 60b is Fgs, the moving distance △Yg becomes △Yg≒△θp×Fgs. The generation accuracy of the origin time Tog of the origin signal SZn is preferably an accuracy (resolution) corresponding to less than 1/2 of the pulse interval distance ΔYp of the spot light SP. Therefore, the scanning speed Vh of the light beam Bgb (spot light SPr) on the photoelectric conversion element DTo is accelerated to about twice the scanning speed Vsp of the spot light SP on the substrate P. That is, it should be set as △Yg≒2. The relationship between △Yp. Therefore, the focal distance Fgs of the lens system GLb is set to about 2 times the focal distance fo of the fθ lens system FT, and the reproducibility of the origin signal SZn is similarly measured.

Fig. 10 shows another drawing unit with the same structure as the drawing unit Un measured in Fig. 9, and the focal distance Fgs of the lens system GLb is changed to 2Fgs≒fo, and the reproducibility is measured in the same manner as in Fig. 9的结果。 The result. The vertical axis and the horizontal axis of FIG. 10 indicate the same as those of FIG. 9, but the 1 scale of the scale of the vertical axis of FIG. 10 is 2nS (5nS in FIG. 9). By making the scanning speed Vh of the spot light SPr on the photoelectric conversion element DTo approximately twice the scanning speed Vsp of the spot light SP on the substrate P, it is calculated based on the distribution of the deviation of each of the interval time △Tma~△Tmh The 3σ value becomes 1.3nS~2.5nS, which is about half the improvement compared with the situation in Fig. 9. Therefore, in this case, if the diameter Φ of the spot light SP is set to 4 μm, the size of 1 pixel Pxy is set to a 4 μm square on the substrate P, and 1 pixel is drawn with 2 pulses of the spot light SP, then the drawing is drawn along The deviation of the position in the main scanning direction of the pattern drawn by the line SLn is halved to about 2.5 μm. Furthermore, the tendency of the deviation of the interval time △Tma~△Tmh shown in Fig. 10 and the tendency of the deviation of the interval time △Tma~△Tmh shown in Fig. 9 above are quite different if viewed in nanoseconds. , Assuming that the reason is that the angle error tendency of each vertex angle between the polygon mirror PM used in the actual measurement of the reproducibility of each of Fig. 9 and Fig. 10 is different. The individual difference (processing error) or the eccentricity error during rotation are different. .

Above, as shown in Fig. 5, the beam Bga for the origin sensor projected on the reflecting surfaces RPa~RPh of the polygon mirror PM is set such that the dimension relative to the rotation direction of the reflecting surfaces RPa~RPh becomes a predetermined thickness ( For example, a parallel beam with a diameter of 1~2mm) can reduce the influence caused by the surface roughness (grinding marks, etc.) of each of the reflective surfaces RPa~RPh, and can accurately detect the average surface angle Variety. On the other hand, in FIG. 5, the diameter of the spot light SPr of the reflected light beam Bgb condensed on the photoelectric conversion element DTo is based on the width of the light receiving surfaces PD1, PD2 in the scanning direction of the beam, and the light receiving surfaces PD1 and PD2. The width of the belt is not affected by it, and it is set appropriately. In order to obtain the signal waveform as shown in Fig. 4[A], the diameter of the spot light SPr in the scanning direction is set to be smaller than the width of the light-receiving surfaces PD1 and PD2 and larger than the width of the insensitive zone.

Furthermore, the intensity distribution in the cross-section of the beam Bga from the semiconductor laser light source LDo as shown in FIG. 5 provided in the beam transmitting portion 60a of FIG. 3 becomes an ellipse with an aspect ratio of about 1:2, so it is preferable to use an ellipse The long axis direction of the shape is consistent with the rotation direction (main scanning direction) of each reflecting surface RPa~RPh of the polygon mirror PM, and the short axis direction of the ellipse is consistent with the direction of the rotation axis AXp of the polygon mirror PM. In this way, even if the height of each reflecting surface RPa~RPh of the polygon mirror PM (the size in the direction of the rotation axis AXp) is small, the light beam Bga can be effectively emitted as the reflected light beam Bgb, and can reach the photoelectric conversion element DTo The number of openings (NA) in the scanning direction of the reflected light beam Bgb is greater than the number of openings (NA) in the non-scanning direction, so the analysis in the scanning direction of the spot light SPr (the direction across the light-receiving surface PD1 and PD2 in Figure 4) can be improved , And make the contrast sharper.

Based on the above, the origin sensor (beam light transmitting unit 60a, light beam receiving unit 60b, and mirror MRa) of the present embodiment shown in FIG. 3 is configured as follows: using the light beam receiving unit 60b (including those shown in FIG. 5 The same lens system GLb and photoelectric conversion element DTo) receive the light beam Bga from the light beam transmitting unit 60a (including the same semiconductor laser light source LDo and collimator lens GLa as in FIG. 5) by the reflecting mirror MRa on the reflecting surface of the polygon mirror PM The reflected beam Bgd after being reflected twice by the RP. Therefore, even when the focal distance Fgs of the lens system GLb into which the reflected light beam Bgd enters is the same as the focal distance fo of the fθ lens system FT, the spot light SPr of the reflected light beam Bgd moving on the photoelectric conversion element DTo can be made The scanning speed Vh is increased to approximately twice the scanning speed Vsp of the spot light SP of the drawing beam LBn. Furthermore, if the focal distance Fgs of the condenser lens (lens system GLb) provided in the light beam receiving portion 60b is longer than the focal distance fo of the fθ lens system FT (that is, the refractive power of the lens system GLb is lower than that of the fθ lens system FT). Ability), the scanning speed Vh of the spot light SPr across the photoelectric conversion element DTo can be set to be more than twice the scanning speed Vsp of the spot light SP on the substrate P.

As described above, according to the present embodiment, it is constructed in such a way that after the origin detection light beam Bga is reflected twice on the reflecting surface RP of the polygon mirror PM by the mirror MRa, the light beam Bga is passed through the condenser lens (lens system GLb ) Make it focus on the photoelectric conversion element DTo into a spot light SPr, so the reproducibility of the generation timing of the origin signal SZn from the photoelectric conversion element DTo is improved, and the drawing position of the pattern in the main scanning direction can be precisely controlled. Furthermore, as for the photoelectric conversion element DTo, it can be used instead of comparing the magnitudes of the output signals STa and STb from the two light-receiving surfaces PD1 and PD2 to generate the origin signal SZn as shown in Figure 4. The signal level of the slit-shaped light-receiving surface is compared with the reference voltage to generate the type of origin signal SZn. In this type of situation, the reproducibility of the origin time Tog of the origin signal SZn has the possibility that the steeper the slope of the rising or falling part of the signal waveform (the shorter the response time), the better, so it is better to make the cross The scanning speed Vh of the point light SPr of the slit-shaped light-receiving surface is faster than the scanning speed Vsp of the point light SP for drawing, and the spot light SPr is concentrated as small as possible by the condenser lens (lens system GLb) Improve the strength per unit area.

[Second Embodiment]

FIG. 11 shows the structure of the origin sensor of the second embodiment. In this embodiment, the polygon mirror PM also has eight reflecting surfaces RPa to RPh. In addition, the same reference numerals are attached to the members having the same functions as those of the first embodiment described above. In FIG. 11, the light beam receiving part 60b as the detection part of the origin sensor is equipped with a mirror MRb that reflects the reflected light beam Bgd reflected by the reflecting surface RP (RPa) of the polygon mirror PM for the second time, as a condenser lens The lens system GLb (the second optical element with refractive power), and the photoelectric conversion element (photodetector) DTo. At the moment when the reflecting surface RPa of the polygon mirror PM becomes the angular position of the timing sequence (origin time Tog) that generates the origin signal SZn, the light beam comes from the light beam sending unit 60a shown in FIG. 5 (not shown in FIG. 11) Bga is reflected by the reflection surface RPa, becomes a reflected light beam Bgb, and enters the re-reflection optical system CE. The re-reflection optical system CE is composed of a first lens system GLc, a second lens system GLd, and a mirror MRa arranged from the side of the polygon mirror PM along the optical axis AXv. The reflected light beam Bgb incident on the re-reflection optical system CE is reflected by the mirror After the MRa is reflected, the reflected beam Bgc is projected to the reflecting surface RPa of the polygon mirror PM again. The reflected light on the reflective surface RPa of the reflected light beam Bgc becomes the reflected light beam Bgd, and is incident on the mirror MRb of the light beam receiving portion 60b, and is condensed into the spot light SPr on the photoelectric conversion element DTo by the lens system GLb.

The front focal point of the first lens system GLc of the re-reflective optical system CE is set at the position of the reflecting surface RPa of the polygon mirror PM (the position where the optical axis AXv crosses the reflecting surface RPa), and the rear focal point of the first lens system GLc is set at Become the position of the pupil face ep. The front focal point of the second lens system GLd is set at the position of the plane ep, and the rear focal point of the second lens system GLd is set at the position of the reflecting surface of the mirror MRa perpendicular to the optical axis AXv. Therefore, the reflected light beam Bgb (parallel light beam) from the reflective surface RPa of the polygon mirror PM diverges after being condensed by the first lens system GLc and becomes the beam waist at the surface ep, enters the second lens system GLd, and becomes a parallel light beam again And reach the mirror MRa. When the principal ray of the reflected light beam Bgb incident on the first lens system GLc has an angle with respect to the optical axis AXv in the XY plane, the principal ray of the reflected light beam Bgb incident on the mirror MRa also maintains its angle with respect to the optical axis AXv angle. The reflected light beam Bgc (parallel light beam) reflected on the mirror MRa enters the second lens system GLd through an optical path symmetrical to the reflected light beam Bgb about the optical axis AXv, diverges and enters the first lens system after the surface ep becomes the beam waist GLc becomes a parallel beam again and is projected to the reflecting surface RPa of the polygon mirror PM. The chief ray of the reflected light beam Bgb from the reflective surface RPa toward the first lens system GLc and the chief ray of the reflected light beam Bgc from the first lens system GLc toward the reflective surface RPa are symmetrical about the optical axis AXv in the XY plane. The reflected light beam Bgc projected on the reflecting surface RPa is reflected by the reflecting surface RPa and becomes a reflected light beam Bgd (parallel light beam), and faces the reflecting mirror MRb.

If the polygon mirror PM (reflecting surface RPa) is rotated clockwise from the state shown in Fig. 11 by an angle Δθe, the reflected light beam Bgb becomes larger from the state shown in Fig. 11 toward the angle formed by the optical axis AXv 2. The direction of the degree of Δθe is inclined and enters the first lens system GLc. Therefore, the incident angle of the reflected light beam Bgb projected to the mirror MRa becomes larger from the state shown in Fig. 11. 2. As a result, the angle formed by the reflected light beam Bgc from the first lens system GLc toward the reflective surface RPa and the optical axis AXv becomes larger from the state of Fig. 11 as a result of the degree of Δθe. 2. The degree of △θe. The reflecting surface RPa of the polygon mirror PM is tilted by the angle Δθe in the clockwise direction from the state of FIG. 11, so the reflected light beam Bgd reflected for the second time by the reflecting surface RPa is tilted from the state of FIG. 11 by an angle of 4. The degree of △θe. Therefore, with respect to the rate of change of the slope of the reflected light beam Bgb first reflected by the reflecting surface RPa of the polygon mirror PM, the rate of change of the slope of the reflected light beam Bgd of the second reflection becomes twice. As a result, the scanning speed Vh of the spot light SPr that traverses the reflected light beam Bgd on the photoelectric conversion element DTo can be about twice the scanning speed Vsp of the spot light of the drawing light beam LBn on the substrate P. Furthermore, the focal distance Fgs of the lens system GLb of the light beam receiving portion 60b is set to be approximately the same as the focal distance fo of the fθ lens system FT, but may be longer than the focal distance fo. In addition, the lens system GLb may not be provided with a mirror MRb, and may be arranged close to the reflecting surface RP of the polygon mirror PM.

As described above, in the present embodiment, the same as the above-mentioned first embodiment is also configured in such a way that the light beam Bga for origin detection is placed on the polygon mirror PM by the re-reflection optical system CE including the mirror MRa. After the reflective surface RP is reflected twice, the lens system GLb condenses the light on the photoelectric conversion element DTo into a point light SPr. Therefore, the reproducibility of the generation timing of the origin signal SZn from the photoelectric conversion element DTo is improved, and the Precisely control the drawing position of the pattern in the main scanning direction.

[Third Embodiment]

Fig. 12 shows the structure of the origin sensor of the third embodiment, and the same reference numerals are attached to the components with the same functions as the first and second embodiments described above. The origin sensor of this embodiment consists of polarization beam splitter BS1 (first light splitting element), polarization beam splitter BS2 (second light splitting element), quarter-wavelength plates QP1, QP2, and lens system GLe (both with It is composed of a first optical element and a second optical element with refractive power, and a photoelectric conversion element DTo. The angular position of the reflecting surface RPa of the polygon mirror PM in FIG. 12 represents the state at which the origin signal SZn from the photoelectric conversion element DTo becomes the origin time Tog as shown in FIG. 4(B). When the rotation axis AXp of the polygon mirror PM is parallel to the Z axis of the coordinate system XYZ, the lens system GLe is arranged parallel to the X axis such that the extension line of the optical axis AXj intersects the rotation axis AXp of the polygon mirror PM. The polarization beam splitter BS1 shaped as a cube is arranged on the +Y direction side with respect to the optical axis AXj, and has a polarization separation surface pb1 inclined at 45 degrees with respect to each of the YZ plane and the XZ plane. The light beam Bga from the light beam sending part 60a not shown is condensed so that the front surface ep of the incident end surface (parallel to the YZ surface) of the polarization beam splitter BS1 becomes the beam waist, and is parallel to the X axis March. The light beam Bga incident on the polarization beam splitter BS1 is set to be linearly polarized light passing through the polarization separation surface pb1. The quarter-wave plate QP1 is arranged so that the exit surface side parallel to the incident end surface of the light beam Bga of the polarization beam splitter BS1 is perpendicular to the optical axis AXj.

The polarization beam splitter BS2 shaped into a cube is arranged on the -Y direction side with respect to the optical axis AXj, and has a polarization separation surface pb2 inclined 45 degrees with respect to each of the YZ plane and the XZ plane. The quarter-wave plate QP2 is connected with The way that the optical axis AXj is vertical is arranged at the same X-direction position as the quarter-wave plate QP1 on the side of the polarization beam splitter BS1. The group of the polarization beam splitter BS1 and the quarter-wave plate QP1 and the group of the polarization beam splitter BS2 and the quarter-wave plate QP2 are arranged symmetrically with respect to a plane parallel to the X axis including the optical axis AXj. Therefore, the polarization separation surface pb1 of the polarization beam splitter BS1 and the polarization separation surface pb2 of the polarization beam splitter BS2 are arranged at an angle of 90 degrees in the XY plane. The photoelectric conversion element DTo as shown in FIG. 4 is arranged such that the light-receiving surfaces PD1 and PD2 are located at the same positions as the surface ep on the -X direction side of the polarization beam splitter BS2. The position of the front focus of the lens system GLe is set on the surface ep, and the position of the front focus is set on the reflecting surface RP (RPa) of the polygon mirror PM.

According to the above configuration, the light beam Bga, which has become divergent light from the surface ep, enters the polarization beam splitter BS1. The light beam Bga passes through the polarization separation surface pb1 and is converted into circularly polarized light by the quarter wave plate QP1, and travels parallel to the optical axis AXj and enters. To the lens system GLe. The light beam Bga passing through the lens system GLe becomes a parallel light beam and is projected to the reflecting surface RP (RPa) of the polygon mirror PM. The reflected light beam Bgb of the light beam Bga reflected by the reflecting surface RPa of the polygon mirror PM is incident on the lens system GLe along the optical path symmetrical about the optical axis AXj and the optical path of the light beam Bga when the reflecting surface RPa is perpendicular to the optical axis AXj, and The beam waist is converged on the same surface as the surface ep. The reflected light beam Bgb passing through the lens system GLe is converted into linearly polarized light in a direction orthogonal to the light beam Bga by the quarter-wave plate QP2, and is incident on the polarization beam splitter BS2. Therefore, the reflected light beam Bgb does not pass through the polarization separation surface pb2 of the polarization beam splitter BS2, but is reflected in the +Y direction, and enters the side surface of the polarization beam splitter BS1. The reflected light beam Bgb reflected on the polarization separation surface pb2 converges so that the position of the optical axis AXj becomes the beam waist, diverges and enters the polarization beam splitter BS1. Since the reflected light beam Bgb becomes linearly polarized light in the direction orthogonal to the light beam Bga, it is reflected by the polarization separation surface pb1 of the polarization beam splitter BS1, and is converted into circularly polarized light by the quarter-wavelength plate QP1 again, and becomes the reflected light beam Bgc. To the lens system GLe.

The reflected light beam Bgc passing through the lens system GLe becomes a parallel light beam passing through the substantially same optical path as the light beam Bga, and is incident on the reflecting surface RPa of the polygon mirror PM. The reflected light beam Bgd of the reflected light beam Bgc again reflected by the reflection surface RPa enters the lens system GLe along the same optical path as the reflected light beam Bgb. The reflected light beam Bgd is converged by the lens system GLe to become the beam waist on the same surface as the surface ep, and is converted into linearly polarized light in the same direction as the beam Bga by the quarter-wavelength plate QP2, and then enters the polarization beam splitter. BS2. Therefore, the reflected light beam Bgd passes through the polarization separation surface pb2 of the polarization beam splitter BS2, becomes the spot light SPr, and is focused on the photoelectric conversion element DTo. In this embodiment, the polarization beam splitters BS1, BS2, quarter-wave plates QP1, QP2, and lens system GLe constitute the re-reflecting optical system CE, and the vertical polarization separation surfaces pb1 and pb2 function as corner mirrors, which are equivalent to The mirror MRa of the first and second embodiments above.

Fig. 13 is a schematic diagram obtained by observing the structure of Fig. 12 in the XY plane, and shows the behavior of each beam when the reflecting surface RPa of the polygon mirror PM is inclined at an angle Δθe from a state perpendicular to the optical axis AXj之图. When the reflective surface RPa is perpendicular to the optical axis AXj, the beam Bga condensed as a spot on the surface ep is between the optical path from the polarization beam splitter BS1 to the reflective surface RPa and the reflected beam Bgc reflected by the polarization separation surfaces pb1 and pb2 The optical path to the reflecting surface RPa overlaps in the XY plane, and the optical path of the reflected light beam Bgb first reflected by the reflecting surface RPa and the optical path of the reflected light beam Bgd secondly reflected by the reflecting surface RPa overlap in the XY plane. Therefore, spot light SPr is generated on the same surface (ep) as the light-receiving surface of the photoelectric conversion element DTo. The position of the spot light SPr in the Y direction is symmetrical about the optical axis AXj and the position where the light beam Bga condenses. If the reflecting surface RPa of the polygon mirror PM is inclined by the angle Δθe from this state, the reflected light beam Bgb initially reflected on the reflecting surface RPa becomes the reflected light beam Bgb' that is deflected (displaced) in the direction away from the optical axis AXj with respect to the original optical path , The reflected light beam Bgc reflected by the polarization separation surfaces pb1 and pb2 becomes the reflected light beam Bgc' that is deflected (displaced) in a direction away from the optical axis AXj with respect to the original optical path (the same optical path as the light beam Bga) and faces the reflection surface RPa. Therefore, the reflected light beam Bgd reflected for the second time by the reflective surface RPa becomes a reflected light beam Bgd' that is deflected (displaced) in a direction further away from the optical axis AXj with respect to the optical path of the reflected light beam Bgb', and reaches the photoelectric conversion element DTo, becoming a spot light SPr'.

When it is assumed that the spot light of the reflected light beam Bgb' initially reflected by the reflective surface RPa is formed in the photoelectric conversion element DTo, relative to the distance that the spot light moves from the position of the spot light SPr, the spot light SPr' can be made from the point The distance moved by the position of the light SPr is doubled. That is, in this embodiment, even when the focal distance Fgs of the lens system GLe is equal to the focal distance fo of the fθ lens system FT, the scanning speed Vh of the spot light SPr' on the photoelectric conversion element DTo can be made equal to The scanning speed Vsp of the spot light SP on the substrate P is twice as high. In this embodiment, the re-reflective optical system CE can be miniaturized, and the origin sensor can be formed into a stable structure.

[Fourth Embodiment]

Figures 14 and 15 show the structure of the origin sensor of the fourth embodiment, and the same symbols are attached to the components with the same functions as the first to third embodiments above. FIG. 14 is a view obtained by observing the configurations of the polygon mirror PM, the fθ lens system FT, the cylindrical lenses CYa, CYb, and the mirror M23 arranged in the same manner as the above embodiments in the XY plane. In this embodiment, at the end (scanning start side) of the maximum scanning range where the drawing light beam LBn scans in the main scanning direction, the re-reflecting optical system CE1 is provided on the cylindrical lens at a position deviated from the drawing line SLn In the space between CYb and the substrate P, the re-reflection optical system CE1 reflects the drawing light beam LBn as the origin detection light beam Bgd through the fθ lens system FT to the polygon mirror PM. The re-reflecting optical system CE1 is composed of a mirror MRw and a cube corner mirror CMw. The mirror MRw deflects the beam LBn projected from the cylindrical lens CYb in the X direction toward the main scanning direction (here Y Direction) reflection, the cube corner mirror CMw has a reflection surface formed at a right angle so that the light beam LBn reflected by the mirror MRw is reflected twice by 90 degrees and then returns to the mirror MRw.

FIG. 14 shows a state in which the polygon mirror PM (reflection surface RPa) is at an angular position such that the drawing light beam LBn is condensed at the drawing start point of the drawing line SLn as a point light SP. Immediately before reaching this state, the light beam LBn reflected by the reflecting surface RPa is incident on the mirror MRw as the origin detection reflected light beam Bgb, and the cube corner mirror CMw turns into a reflected light beam Bgc parallel to the light beam Bgb and folds back. And it is incident on the mirror MRw again. The reflected light beam Bgc reflected by the mirror MRw passes through the cylindrical lens CYb and the fθ lens system FT and is projected to the reflecting surface RPa of the polygon mirror PM. The reflected light beam Bgd of the light beam Bgc reflected by the reflective surface RPa returns to the mirror M23 at an angle inclined with respect to the optical path of the original light beam LBn(Bga) projected from the cylindrical lens CYa. The reflected light beam Bgd is condensed by the lens system GLb and received by the photoelectric conversion element DTo. The original light beam LBn (Bga) projected from the cylindrical lens CYa is controlled in such a way that it oscillates from the light source device LS at the timing when it is incident on the mirror MRw. In addition, the apex angle of the corner cube CMw is set on the surface Pu corresponding to the surface of the substrate P, and the light beam LBn (Bga) is condensed into a point light on the surface Pu.

FIG. 15 is a diagram schematically showing the optical paths of the light beams in FIG. 14. To simplify the description, the illustration of the cylindrical lens CYb and the mirror MRw are omitted. In FIG. 15, the reflection surface RPa of the polygon mirror PM becomes the angle at which the drawing beam LBn is used as the origin detection beam Bga and incident on the reflection surface CMa of the corner mirror CMw. At this time, the incident angle of the chief ray Lpa of the light beam Bga to the reflection surface RPa becomes an angle θβ, and the reflection angle of the chief ray Lpb of the reflected light beam Bgb reflected on the reflection surface RPa also becomes an angle θβ. The reflected light beam Bgb is reflected on the reflective surface CMa of the cube corner mirror CMw and becomes a light spot on the surface Pu' to be condensed, and then diverges and enters the other reflective surface CMb. The chief ray Lpc of the reflected light beam Bgc of the light beam Bgb reflected on the reflective surface CMb and the chief ray Lpb of the reflected light beam Bgb are incident on the fθ lens system FT in parallel. After passing through the fθ lens system FT, the reflected light beam Bgc becomes a substantially parallel light beam in the XY plane (main scanning surface), and enters the reflecting surface RPa at an incident angle larger than the angle θβ. Therefore, the reflected light beam Bgd (principal ray Lpd) of the light beam Bgc reflected on the reflection surface RPa faces the mirror M23 at a reflection angle larger than the angle θβ. The reflected light beam Bgd reflected by the mirror M23 is condensed into a spot light SPr on the photoelectric conversion element DTo in the XY plane by the lens system GLb. Furthermore, the focal distance Fgs of the lens system GLb is set to be the same as or greater than the focal distance fo of the fθ lens system FT.

As shown in Fig. 15, the light beam Bgb (LBn) projected from the fθ lens system FT to the side of the substrate P is set to be telecentric, so the chief ray Lpb and fθ lens system from the fθ lens system FT to the reflecting surface CMa of the corner mirror CMw The optical axis AXf of FT is parallel. Therefore, the chief ray Lpc of the light beam Bgc from the reflecting surface CMb of the corner cube CMw toward the fθ lens system FT is also parallel to the optical axis AXf. If between the fθ lens system FT and the corner mirror CMw, the light beam Bgb is incident on the reflection surface CMa of the corner mirror CMw and scanned in the direction of arrow A1, then it will be reflected by the reflection surface CMb of the corner mirror CMw The beam Bgc scans in the direction of arrow A2, which is opposite to arrow A1. Therefore, as in this embodiment, even when the drawing light beam LBn is used as the origin detection light beam (Bga, Bgb, Bgc, Bgd), it can be arranged on the image surface side of the fθ lens system FT. (Substrate P side) The corner cube CMw returns the origin detection beam to the reflecting surface RP of the polygon mirror PM, and accelerates the scanning speed Vh of the spot light SPr across the photoelectric conversion element DTo to the point of the drawing beam LBn The scanning speed of light SP is about twice that of Vsp.

In this embodiment, since the origin detection light beams (Bga, Bgb, Bgc) are detected by the photoelectric conversion element DTo through the fθ lens system FT, the origin time Tog of the origin signal SZn is at the main point including the fθ lens system FT. The timing of the influence of optical aberrations in the scanning direction is generated. Therefore, precise drawing is performed including errors caused by optical aberrations in the main scanning direction included in the pattern drawn along the drawing line SLn.

[Fifth Embodiment]

Fig. 16 shows the structure of the origin sensor of the fifth embodiment, and the same symbols are attached to the components with the same functions as the first to fourth embodiments above. 16 is a view obtained by observing the configurations of the polygon mirror PM, the fθ lens system FT, the cylindrical lenses CYa, CYb, and the mirror M23 arranged in the same manner as the above embodiments in the XY plane. In this embodiment, the corner mirror CMw and the mirror MRw similar to those in FIGS. 14 and 15 are also arranged in the space between the cylindrical lens CYb and the substrate P and on the side of the scanning start position of the spot light SP that draws the line SLn. Furthermore, in the present embodiment, similar to the first and second embodiments, the beam transmitting unit that outputs the origin detection light beam Bga (parallel light beam) from continuous light emission of a wavelength different from the drawing light beam LBn 60a is projected to the reflecting surface RP (RPa) of the polygon mirror PM through the mirror M33. The mirror M33 is arranged at an inclination of 45 degrees with respect to the XY plane in FIG. 16, and the light beam Bga from the light beam transmitting unit 60a is projected to the mirror M33 from the Z direction. When the reflecting surface RP (RPa) of the polygon mirror PM becomes a specific angular position, the reflected light beam Bgb at the reflecting surface RP (RPa) of the light beam Bga passes through the fθ lens system FT and the cylindrical lens CYb toward the reflecting mirror MRw. The light beam Bgb reflected by the mirror MRw and incident on the corner mirror CMw becomes the reflected light beam Bgc and is folded back. After being reflected by the mirror MRw, it passes through the cylindrical lens CYb and the fθ lens system FT and returns to the reflecting surface RP (RPa) of the polygon mirror PM. ). The reflected light beam Bgd of the light beam Bgc returning to the reflective surface RP (RPa) travels in a direction inclined with respect to the light beam Bga, is reflected by the mirror M34, passes through the lens system GLb, and is focused on the photoelectric conversion element DTo as a point light.

In the case of the configuration of FIG. 16, the light beam Bgc returning to the reflecting surface RP (RPa) of the polygon mirror PM is projected to XY on the reflecting surface RP (RPa) of the light beam Bga projected from the light beam transmitting portion 60a The same position in the plane. In this embodiment, the wavelength of the origin detection light beam Bga (Bgb, Bgc, Bgd) can be made longer than the wavelength of the drawing light beam LBn, which can reduce the situation where excess light is imparted to the photosensitive layer of the substrate P. Furthermore, if the wavelength of the origin detection light beam Bga is different from the wavelength of the drawing light beam LBn, chromatic aberration caused by the cylindrical lens CYb and the fθ lens system FT occurs, and the point light SP of the drawing light beam LBn starts The position (timing) on the substrate P for drawing and the timing of the origin signal SZn at the time Tog will produce a fixed time error corresponding to the error in the main scanning direction (chromatic aberration of magnification) caused by chromatic aberration . However, as long as the time error is fixed, it can be accurately corrected by adjusting the delay time from the origin time Tog to the pattern drawing start time point in nanoseconds.

As described above, in this embodiment, the corner mirror CMw arranged on the image surface side (substrate P side) of the fθ lens system FT can also be used to return the origin detection light beam Bga to the reflecting surface RP of the polygon mirror PM. The scanning speed Vh of the spot light SPr traversing the photoelectric conversion element DTo is increased to approximately twice the scanning speed Vsp of the spot light SP of the drawing light beam LBn.

[Variations of the fifth embodiment]

Fig. 17 shows the configuration of a modified example of the origin sensor of the fifth embodiment, and the same reference numerals are attached to the components with the same functions as the first to fifth embodiments above. In FIG. 17, the chief ray Lpc of the reflected beam Bgc returning from the corner mirror CMw to the fθ lens system FT (cylindrical lens CYb) is slightly in the main scanning direction from the state parallel to the optical axis AXf of the fθ lens system FT In the method of tilting, the two reflecting surfaces CMa and CMb of the cube corner mirror CMw are slightly inclined from 45 degrees with respect to the optical axis AXf. That is, the reflected light beam Bgc, which is reflected on the reflecting surface CMb of the corner mirror CMw, is changed from the telecentric state to the non-telecentric state in the main scanning direction. Thereby, the reflected light beam Bgc (parallel light beams in the XY plane) that reaches the reflecting surface RP (RPa) of the polygon mirror PM through the fθ lens system FT is projected onto the reflecting surface RP (RPa) and the original light beam Bga is projected The part that deviates from the part. Therefore, when the reflected light beam Bgd of the light beam Bgc reflected by the reflecting surface RP (RPa) of the polygon mirror PM is reflected by the reflecting mirror M23 and faces the photoelectric conversion element DTo, the chief ray Lpa of the original light beam Bga and the chief ray of the reflected light beam Bgd Compared with the state shown in Figure 15 above, Lpd is separated at a larger angle. Therefore, it is easy to install the structure of the light beam receiving portion 60b that detects the reflected light beam Bgd, especially the mirror that causes the reflected light beam Bgd reflected by the mirror M23 to face the lens system GLb and reflect it, and the degree of freedom in the arrangement of the lens system GLb is improved.

As shown in Fig. 17, the configuration in which the two reflecting surfaces CMa and CMb of the cube corner mirror CMw are slightly inclined from 45 degrees with respect to the optical axis AXf can also be applied to the above-mentioned Figs. 14 and 15 The fourth embodiment.

[Sixth Embodiment]

Fig. 18 shows the structure of the origin sensor of the sixth embodiment, and the same symbols are attached to the components with the same functions as the first to fifth embodiments above. In this embodiment, as shown in FIG. 18, the origin sensor is configured as follows: in a state where the drawing light beam LBn is projected to one reflecting surface RPh of the polygon mirror PM through the reflecting mirror M23, the original The spot detection beam Bga (parallel beam) is projected to the reflection surface RPh adjacent to the reflecting surface RPh of the polygon mirror PM. The reflection surface RPa and the adjacent reflecting surface RPa (the first one) reflecting surface RPb reflect two surface. The light beam Bga projected as a parallel light beam from the light beam transmitting unit 60a not shown in the figure is reflected by the reflection surface RPa of the polygon mirror PM, becomes a reflected light beam Bgb, and is projected to the mirror MRa. The reflected light beam Bgc at the reflecting mirror MRa of the light beam Bgb is projected to the reflecting surface RPb of the polygon mirror PM, and the reflected light beam Bgd at the reflecting mirror MRb of the light beam Bgc is converted into a spot light SPr by the lens system GLb and focused on the photoelectric conversion element On DTo. In this embodiment, the origin detection light beam Bga is also reflected twice at a different angle from the reflecting surface RP of the polygon mirror PM, so even if the focal distance Fgs of the lens system GLb is approximately the same as the focal distance fo of the fθ lens system FT It is also possible to increase the scanning speed Vh of the spot light SPr that traverses the photoelectric conversion element DTo to about twice the scanning speed Vsp of the spot light SP of the drawing light beam LBn.

[Other Modifications]

It can also replace the polygon mirror PM, and in the beam scanning device (pattern drawing device) formed by the galvanometer mirror (scanning member), for example, the origin detection sensor (lens system) shown in Figure 12 above is provided GLe, polarization beam splitters BS1, BS2, quarter-wavelength plates QP1, QP2, photoelectric conversion element DTo) are used as origin detection sensors that detect the moment when the galvanometer mirror reaches a predetermined angle as the origin position. The beam scanning device formed by the galvanometer mirror is also constructed in the following way: the beam for drawing (or processing) is deflected one-dimensionally by the reflecting surface of the galvanometer mirror reciprocating through the fθ lens system FT The light is condensed into a spot light on the substrate P (irradiated body) by using an optical system for scanning. In the case of galvanometer mirrors, the back side of the reflective surface of the light beam used for reflection drawing (or processing) can also be a reflective surface, so it can be easily used in addition to the origin detection sensor as shown in Figure 12 Ground the origin detection sensor shown in Figure 3 and Figure 11. In addition, as shown in FIG. 14 and FIG. 16, it can also be set as an origin detection sensor that transmits a scanning optical system such as fθ lens system FT.

In addition, in each of the above embodiments, the origin detection light beam Bga is reflected twice on the reflecting surface RP of the polygon mirror PM and then received by the photoelectric conversion element DTo, but it may be reflected by the photoelectric conversion element DTo after three times or more and received by the photoelectric conversion element DTo. . In this case, for example, if the light beam Bga reflected on the first reflecting surface (RPh) of the polygon mirror PM is reflected on the second reflecting surface (RPa) as shown in Fig. 18 and the re-reflecting optical system as shown in Fig. 11 The CE combination can easily form an origin detection sensor with three reflections.

AXo‧‧‧Central axis

AXp‧‧‧Rotation axis

DR‧‧‧Rotating drum

EX‧‧‧Exposure device (pattern drawing device)

FT‧‧‧fθ lens system (scanning lens for drawing)

IM1~IM6‧‧‧Entrance mirror

LS‧‧‧Light source device

M1~M12‧‧‧Mirror

M20~M24‧‧‧Mirror

OS1~OS6‧‧‧Optical components for selection

P‧‧‧Substrate (irradiated body)

PM‧‧‧Polygon mirror

RP‧‧‧Reflecting surface

SL1~SL6‧‧‧Drawing line

TR‧‧‧Absorber

U1~U6‧‧‧Drawing unit

X, Y, Z‧‧‧direction

Claims (18)

A beam scanning device is provided with a scanning optical system that deflects the reflective surface of a scanning member with a variable angle to a processing beam incident, and condenses the processing beam on an irradiated body into a light spot, and according to the above The angle change of the reflective surface of the scanning member causes the light spot to be scanned, and it is equipped with a light beam sending unit that projects a detection light beam for detecting that the reflective surface of the scanning member becomes the origin of a predetermined angle to the scanning member A reflection surface; a light beam reflection portion which makes the detection light beam reflected on the reflection surface of the scanning member incident and reflects to the reflection surface of the scanning member; and a detection portion which is based on being reflected again on the reflection surface of the scanning member The reflected light beam of the detection light beam outputs an origin signal representing the origin. For example, the light beam scanning device of the first item of the scope of patent application, wherein the light beam sending part is provided with a first optical element, and the first optical element is provided for shaping the light beam from the continuous light-emitting detection light source into a parallel light beam as the detection Use the refractive power of the beam. For example, the light beam scanning device of the second item of the scope of patent application, wherein the detection unit includes: a photodetector that receives the reflected light beam reflected for the second time on the reflective surface of the scanning member and outputs the origin signal; and second optics An element having refractive power for condensing the reflected light beam on the photodetector. For example, the light beam scanning device of the third item of the scope of patent application, wherein the light beam sending part is provided with a first light splitting element, and the first light splitting element is arranged in such a way that the light beam from the detection light source is directed toward the first optical element The detection section includes a second light splitting element, and the second light splitting element is configured to cause the reflected light beam incident on the second optical element to be reflected for the second time by the reflective surface of the scanning member toward the photodetector Arranged, the second light splitting element has a splitting surface for splitting the reflected light beam initially reflected by the reflective surface of the scanning member and incident on the second optical element toward the first light splitting element, and the first light splitting element has The reflected light beam from the second optical splitting element is directed toward a splitting surface where the first optical splitting element is split. For example, the light beam scanning device of the 4th patent application, wherein the first light splitting element and the second light splitting element are polarizing beam splitters arranged in such a way that the respective separating surfaces are formed at right angles. For example, the light beam scanning device of the 5th item of the scope of patent application, wherein the first optical element and the second optical element are respectively composed of two parts separated by the optical axis of a condensing optical system. For example, the light beam scanning device of any one of items 3 to 6 in the scope of patent application, wherein the focal distance of the second optical element is set to be the same as or longer than the focal distance of the scanning optical system. For example, the light beam scanning device of the first item of the scope of patent application, wherein the scanning member is a rotating polygon mirror that rotates around a central axis of rotation, and the light beam reflecting part is composed of the detection light beam reflected by the first reflecting surface of the rotating polygon mirror. The reflected light beam is arranged such that it is reflected toward the second reflecting surface of the rotating polygon mirror which is different from the first reflecting surface. A pattern drawing device is provided with a scanning optical system that deflects a light beam for drawing that is deflected by a reflective surface of a scanning member with a variable angle, and condenses the light beam for drawing on a substrate as a light spot, and one surface is based on the scanning The angle change of the reflecting surface of the component causes the light spot to scan, while the intensity of the drawing light beam is adjusted according to the pattern, and the pattern is drawn on the substrate, and it is equipped with a light beam transmitting part, which will be used to detect the scanning component. The detection light beam whose reflection surface becomes the origin of a predetermined angle is projected to the reflection surface of the scanning member; a light beam reflection portion that causes the detection light beam reflected on the reflection surface of the scanning member to enter and is reflected toward the reflection of the scanning member A detection unit, which outputs an origin signal representing the origin based on the reflected light beam of the detection beam again reflected on the reflective surface of the scanning member; and a control unit, which controls the use of the light based on the origin signal Click on the depiction of the above-mentioned pattern. For example, the pattern drawing device of item 9 of the scope of patent application, wherein the light beam sending part is provided with a first optical element, and the first optical element is provided for shaping the light beam from the continuous light-emitting detection light source into a parallel light beam as the detection Use the refractive power of the beam. For example, the pattern drawing device of item 10 in the scope of patent application, wherein the detection unit includes: a photodetector, which receives the reflected light beam secondly reflected on the reflective surface of the scanning member and outputs the origin signal; and second optics An element having refractive power for condensing the reflected light beam on the photodetector. For example, the pattern drawing device of claim 10, wherein the light beam transmitting section includes a first light splitting element, and the first light splitting element is arranged in such a way that the light beam from the detection light source is directed toward the first optical element The detection section includes a second light splitting element, and the second light splitting element is configured to cause the reflected light beam incident on the second optical element to be reflected for the second time by the reflective surface of the scanning member toward the photodetector Arranged, the second light splitting element has a splitting surface for splitting the reflected light beam initially reflected by the reflective surface of the scanning member and incident on the second optical element toward the first light splitting element, and the first light splitting element has The reflected light beam from the second optical splitting element is directed toward a splitting surface where the first optical splitting element is split. For example, the pattern drawing device of the 12th patent application, wherein the first light splitting element and the second light splitting element are polarizing beam splitters arranged such that the respective separating surfaces are formed at right angles. For example, the pattern drawing device of item 13 of the scope of patent application, wherein the first optical element and the second optical element are respectively composed of two parts separated by the optical axis of a condensing optical system. For example, the pattern drawing device of any one of the 11th to 14th items in the scope of patent application, wherein the focal distance of the second optical element is set to be the same as or longer than the focal distance of the scanning optical system. A beam scanning device which utilizes a scanning optical system to condense a processing beam deflected by one of a plurality of reflecting surfaces of a rotating polygon mirror into a light spot on an irradiated body, and by the above-mentioned rotating polygon The rotation of the mirror causes the light spot to be scanned, and it is provided with a light beam transmitting unit that projects a detection light beam for detecting each of the plurality of reflecting surfaces of the rotating polygonal mirror as the origin of a predetermined angle to the rotation The reflecting surface of the polygonal mirror; a beam reflecting portion that makes the detection light beam reflected on the reflecting surface of the rotating polygonal mirror incident and reflecting to the reflecting surface of the rotating polygonal mirror; and a beam detecting portion that is received by the rotating polygonal mirror The reflected light beam of the above-mentioned detection light beam reflected by the reflecting surface of the mirror again, and an origin signal representing the above-mentioned origin is output. For example, the beam scanning device of the 16th patent application, wherein the light beam sending unit has a first optical element having refractive power for shaping the detection beam into a parallel beam, and the detection unit has: a photodetector, which Receiving the reflected light beam of the detection light beam and outputting the origin signal; and a second optical element having a refractive power for condensing the reflected light beam on the photodetector. For example, the light beam scanning device in the scope of patent application, wherein the focal distance of the second optical element of the detection unit is the same as or longer than the focal distance of the scanning optical system.

Images