JP2001305447A - Laser plotting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser plotting device capable of correcting the nonuniformity of recording density of scanning pixels with high accuracy. SOLUTION: This laser plotting device modulates a laser beam with an acoustooptical modulator 53 based on raster data read by a plotting clock signal (f), deflects the modulated laser beam in the main scanning direction by a polygon mirror 67, irradiates the substrate on a plotting stage 5 with the laser beam, then displaces the plotting stage 5 in the subscanning direction to plot a pattern. The laser plotting device is provided with a plotting clock generating circuit 123 to adjust the plotting clock (f) in the correction part among the plotting clocks (f) for one scanning line to a desired frequency according to the set value (k) corresponding to the increase of a phase (correction data of position-deviation).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser drawing apparatus for drawing a desired pattern by irradiating a processing object such as a printed wiring board with a laser beam, and more particularly to a drawing pattern due to distortion of a scanning optical system. The present invention relates to a technique for correcting the positional deviation of a high precision.

[0002]

2. Description of the Related Art As a conventional laser writing apparatus, for example, there is one as disclosed in Japanese Patent Application Laid-Open No. 10-80781. This apparatus includes a table on which a printed wiring board on which a photosensitive material is adhered, an imaging optical system including a polygon mirror and an fθ lens for deflecting a laser beam for drawing in the main scanning direction, and an auxiliary table. And a moving mechanism for moving in the scanning direction. This apparatus modulates a laser beam based on raster data read by a drawing clock, deflects the modulated laser beam in the main scanning direction to irradiate a printed wiring board on a table, and simultaneously modulates the laser beam in the sub-scanning direction. By moving the table, a desired pattern is drawn on the printed wiring board.

In order to properly draw a drawing pattern having a predetermined size and shape on a printed wiring board, it is important that the drawing pattern is drawn on the printed wiring board with pixels arranged at equal intervals and evenly. It is mentioned as a condition. However, in an actual apparatus, there is a non-uniformity in which a drawing pattern is drawn on a printed wiring board with pixels having uneven spacing and non-uniform arrangement. (Drawing pattern displacement = scanning distortion) occurs. One of the causes of the non-uniformity is, for example, an fθ lens. The fθ lens is used to make the spot of the laser beam linearly move on the printed wiring board at a constant speed in the main scanning direction. As this fθ lens,
It is desired to have a scanning optical characteristic having a linear constant speed as shown by a broken line in FIG. However, as shown by the solid line in FIG. 15A, the actual scanning optical characteristic of the fθ lens is such that, at the fine level, the spot of the laser beam is at a minute level (a time of about a pixel unit) in one scanning period. It does not have a perfect linear constant velocity but has distortion. As a result, as shown by the solid line in FIG. 15B, the main scanning speed of the beam spot has such a characteristic that it becomes faster at the end of one scanning period. for that reason,
If the drawing clock has a constant frequency, unevenness occurs in that the drawing pattern is drawn on the printed wiring board with pixels having uneven spacing and non-uniform arrangement, and the characteristics of the scanning pixels due to the characteristics of the fθ lens. Recording density unevenness occurs.

Therefore, in order to correct the recording density unevenness of the scanning pixels, the apparatus of the prior art uses a phase shift of a drawing clock of 2π (one cycle) or less based on deviation data of a pixel arrangement pitch actually measured. Calculating means for calculating the position to be shifted in unit as phase shift start position data, and controlling the output of the drawing clock so as to shift the phase of the drawing clock in accordance with the phase shift start position data and to correct the pixel arrangement shift And clock pulse output control means.

In this apparatus, the processing for correcting the recording density unevenness of the scanning pixels is performed as follows. Actually draw the grid-like drawing pattern, measure the position of each intersection of the grid-like drawing pattern, and position the intersection of the actually measured grid-like drawing pattern with the ideal grid-like drawing pattern The deviation data of the pixel array pitch is obtained from the deviation from the above. Based on the pixel array pitch shift data, the arithmetic means shifts the position of the drawing clock phase in units of 2π or less (the positions of a plurality of target drawing clocks in one scan line). Calculate as start position data. The clock pulse output control means corrects the phases of the drawing clocks at a plurality of target positions in one scan line specified by the phase shift start position data at predetermined intervals in accordance with the shift amount of the pixel array pitch. The output of the drawing clock is controlled so as to shift to either the negative side or the negative side so as to correct the deviation of the pixel arrangement.
In this way, by shifting the phases of the drawing clocks at a plurality of target locations in one scanning line, the pixels are adjusted so as to be arranged at equal intervals and evenly, and are arranged at equal intervals and evenly. The drawing pattern is drawn on the printed wiring board with the pixels that have been adjusted so as to be close to each other, and the recording density unevenness of the scanning pixels is corrected.

[0006]

However, the prior art having such a structure has the following problems. The process of correcting the recording density unevenness of the scanning pixels is performed by changing the phase of the drawing clock of a part of one scanning line at a predetermined interval according to the shift amount of the pixel arrangement pitch and at the positive side or the negative side. It is done by shifting to. Specifically, the clock signal is sequentially phase-shifted (delayed) by a predetermined time (about one-tenth of one cycle of the drawing clock) to generate a plurality of types of clock signals,
A clock signal having a desired phase shift amount is selected from these signals, and the drawing clock is generated by applying the selected clock signal having the desired phase shift amount to a part of the drawing clock in one scanning line. It is done by outputting as. Therefore, there is a problem that a plurality of types of clock signals that are phase-shifted (delayed) are required. Further, the phase shift of the clock signal is 1 in one cycle.
Since the control can be performed only with a resolution of about 1/0 (a unit level of about 1/10 of one pixel), there is a problem that the recording density unevenness of the scanning pixel cannot be corrected with higher accuracy. Considering the case where this conventional apparatus is used for multi-beam drawing in which a plurality of laser beams are simultaneously drawn in one scan, the clock pulse output control means is required for each laser beam. Since the control circuit for controlling becomes complicated, there is a problem that the realization cost increases.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and has as its object to provide a laser drawing apparatus which performs highly accurate correction processing of uneven recording density of scanning pixels.

[0008]

The present invention has the following configuration in order to achieve the above object. That is, the laser drawing apparatus according to the first aspect modulates a laser beam based on a drawing signal generated by raster data read out by a drawing clock of a predetermined frequency, and deflects the modulated laser beam in a main scanning direction. While deflecting in the direction to irradiate the processing object on the mounting table,
In a laser drawing apparatus that draws a desired pattern on the processing target by relatively moving a laser beam and a mounting table in a sub-scanning direction by a moving unit, a correction clock in a writing clock for one scanning line is used. Drawing clock,
It is characterized by comprising a signal adjusting means for adjusting to a frequency corresponding to the displacement correction data.

According to a second aspect of the present invention, in the laser writing apparatus according to the first aspect, the signal adjusting means is configured to set a frequency setting value of a clock at a correction position among clocks for one scanning line. , As a displacement correction data, a direct digital synthesizer for generating a clock having a frequency corresponding to the frequency setting value from the memory, a clock from the direct digital synthesizer is multiplied and output as a drawing clock And a multiplying means.

According to a third aspect of the present invention, there is provided the laser writing apparatus according to the first or second aspect, wherein the signal adjusting means is provided for each of a plurality of laser beams for simultaneous scanning and writing. It is characterized by the following.

According to a fourth aspect of the present invention, in the laser writing apparatus according to any one of the first to third aspects, the deflecting means is a scanning system including a polygon mirror. It is characterized by comprising storage means for storing positional deviation correction data for each surface.

According to a fifth aspect of the present invention, in the laser writing apparatus according to the fourth aspect, a scanning speed distribution detecting means for detecting a scanning speed distribution of a laser beam for each surface of the polygon mirror is provided. Computing means for calculating positional deviation correction data for each surface of the polygon mirror such that the drawing pitch of each surface of the polygon mirror detected by the scanning speed distribution detecting means by the laser beam is constant. It is assumed that.

According to a sixth aspect of the present invention, in the laser writing apparatus according to any one of the first to third aspects, the deflecting means is a scanning system including a polygon mirror, and the laser beam for writing is provided. And a generating means for receiving a reference laser beam through the polygon mirror and generating a drawing clock for each surface of the polygon mirror.

According to a seventh aspect of the present invention, there is provided the laser writing apparatus according to any one of the first to sixth aspects, wherein an expansion / contraction amount detecting means for detecting an expansion / contraction amount of the processing object; A calculating means for correcting displacement correction data in accordance with the amount of expansion and contraction detected by the amount of expansion and contraction detection means.

[0015]

The operation of the first aspect of the present invention is as follows. The signal adjusting means adjusts the drawing clock of the correction part among the drawing clocks of one scanning line to a frequency corresponding to the positional deviation correction data. As a result, the drawing pitch by the laser beam is adjusted to be constant, and the displacement of the drawing pattern due to the distortion of the scanning optical system is corrected with high accuracy.

According to the second aspect of the present invention, the memory unit holds the frequency setting value of the clock at the correction position among the clocks for one scanning line as the positional deviation correction data. A direct digital synthesizer
A clock having a frequency corresponding to a frequency setting value from the memory unit is generated. The multiplying means multiplies the clock from the direct digital synthesizer and outputs it as a drawing clock. Therefore, the frequency of the drawing clock can be set with high resolution, and the displacement of the drawing pattern can be corrected in minute units of one pixel or less of the raster data, and the displacement of the drawing pattern due to the distortion of the scanning optical system can be accurately detected. A configuration for correction can be realized.

According to the third aspect of the present invention, the signal adjusting means is provided for each of a plurality of laser beams for simultaneous scanning and drawing. Therefore, in multi-beam writing using a plurality of laser beams, the writing clock of the correction position of each laser beam is adjusted to a frequency corresponding to the position shift correction data, and the position shift of the writing pattern of each laser beam is corrected with high accuracy. Is done.

Further, according to the apparatus described in claim 4, the storage means stores the positional deviation correction data for each surface of the polygon mirror. Therefore, the drawing clock is adjusted for each polygon mirror surface in accordance with the stored misregistration correction data for each surface of the polygon mirror, and the drawing pattern due to the distortion of the scanning optical system such as the rotation accuracy of the polygon mirror and the rotation unevenness of each surface. Is accurately corrected for each surface of the polygon mirror.

According to a fifth aspect of the present invention, the scanning speed distribution detecting means detects the scanning speed distribution of the laser beam for each surface of the polygon mirror. The calculating means calculates positional deviation correction data for each surface of the polygon mirror such that the drawing pitch of each surface of the polygon mirror detected by the scanning speed distribution detecting means by the laser beam is constant. Accordingly, the displacement correction data for each surface of the polygon mirror is automatically calculated, and the drawing pitch of the laser beam on each surface of the polygon mirror is made constant according to the calculated displacement correction data for each surface of the polygon mirror. The drawing clock is adjusted so that the positional deviation of the drawing pattern due to the distortion of the scanning optical system such as the rotation accuracy of the polygon mirror and the rotation unevenness of each surface is corrected with high accuracy for each surface of the polygon mirror.

According to the apparatus described in claim 6, the generating means receives a reference laser beam different from the drawing laser beam via the polygon mirror, and generates a reference laser beam for each surface of the polygon mirror. Generate a drawing clock. The signal adjusting means adjusts the drawing clock of the correction position among the drawing clocks for one scanning line for each surface of the polygon mirror generated by the generating means, to a frequency corresponding to the positional deviation correction data. As described above, even in the case of a laser drawing apparatus that receives a reference laser beam through a polygon mirror and generates a drawing clock, thereby canceling a drawing position shift due to a change in scanning speed for each polygon surface, The pitch error in the generation of the drawing clock by the generation unit is corrected, the generation position shift of the drawing clock is corrected,
The displacement of the drawing pattern is corrected with high accuracy.

Further, according to the invention of claim 7, the expansion / contraction amount detecting means detects the expansion / contraction amount of the processing object. The calculating means corrects the displacement correction data according to the amount of expansion and contraction detected by the amount of expansion and contraction detecting means. Therefore, the displacement of the drawing pattern due to the distortion of the scanning optical system is corrected with high accuracy, and the drawing pattern is scaled down with high accuracy according to the dimensional change of the processing target.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. A printed wiring board manufacturing apparatus, which is an example of a laser drawing apparatus according to the present invention, has first to third correction functions as described below. (1) The first correction function is a function of correcting a positional deviation of a drawing pattern due to a distortion of a scanning optical system. (First Correction Example) (2) The second correction function corrects, among the distortions of the scanning optical system, the positional deviation of the drawing pattern due to the rotational accuracy of the polygon mirror and the rotational unevenness of each surface. Function. (Second Correction Example) (3) The third correction function is a function of correcting a position shift of a drawing pattern due to a distortion of a scanning optical system and correcting the drawing pattern in accordance with a dimensional change of a printed wiring board. . (Third Correction Example) A printed wiring board manufacturing apparatus having such first to third correction functions is configured as follows.

FIG. 1 is a perspective view showing a schematic configuration of a printed wiring board manufacturing apparatus as an example of a laser drawing apparatus according to the present invention, FIG. 2 is a plan view thereof, and FIG. 3 is a side view thereof. FIG. 4 is a side view showing a schematic configuration of the position correcting mechanism, FIG. 5 is a side view thereof, and FIG. 6 is a front view thereof.

As shown in FIG. 1, the printed wiring board manufacturing apparatus according to this embodiment is roughly divided into a drawing stage 5 on which a printed wiring board (object to be processed) S on which a photosensitive material is applied is mounted. An imaging optical system 21 including a polygon mirror 67 and an fθ lens 68 for deflecting the drawing laser beam LB in the main scanning direction (x direction);
A moving mechanism for moving in the sub-scanning direction (y direction);
It comprises a data processing unit 101 for processing artwork data of a printed wiring board designed using D (Computer Aided Design), and a drawing control unit 102 for performing drawing control based on the data from the data processing unit 101. ing.

The moving mechanism of the drawing stage 5 is configured as follows. A pair of guide rails 3 is provided on the upper surface of the base 1 of the apparatus, and a feed screw 9 rotated by a servomotor 7 is provided between the guide rails 3. The drawing stage 5 is screwed to the feed screw 9 at its lower part. As shown in FIG. 3, the drawing stage 5 includes a stage base 10 to which a feed screw 9 is screwed and slidably mounted along the guide rail 3 and a rotation for rotating around a vertical z-axis. Mechanism 11 and elevating mechanism 13 for elevating and lowering in the vertical z direction
And a mounting table 15 for adsorbing and mounting the printed wiring board S on the uppermost portion.

The moving mechanism including the guide rail 3, the servo motor 7 and the feed screw 9 corresponds to a moving means in the present invention.

In the y direction (sub-scanning direction) in which the drawing stage 5 is moved by the drive of the servo motor 7,
An imaging optical system 2 that irradiates a drawing laser beam LB downward while deflecting it in the x direction (main scanning direction) in Y.
1 is provided. The imaging optical system 21 is disposed above the base 1 by a gate-shaped frame. When the servo motor 7 is driven, the drawing stage 5 is connected to the imaging optical system 2.
It is designed to advance and retreat for one.

As shown in FIG. 3, an alignment scope unit 31 is provided on the base 1 so as to cover the drawing stage 5 at the standby position. The alignment scope unit 31 includes four alignment scopes 33, 35, and 3 that can move independently in a horizontal plane.
7,39. Each alignment scope 33,
35, 37, and 39 are CCDs (charge coupled devices).
) Cameras 33a, 35a, 37a, 39a and lens portions 33b, 35b, 37b, 39b are provided. These alignment scopes 33, 35, 37, 39
Alignment holes (alignment marks) formed at four corners of printed wiring board S mounted on drawing stage 5
By measuring the position of A and calculating the amount of positional shift of the printed wiring board S placed on the drawing stage 5 to correct the "shift" or to detect the amount of expansion and contraction of the printed wiring board S Used.

Next, the image forming optical system 21 will be described.
The laser light source 41 is, for example, a solid-state laser having a wavelength of 532 μm using a semiconductor as an excitation light source. This laser light source 41
The laser beam LBa emitted from the laser beam LBa is changed in direction by approximately 90 ° by the corner mirror 43 and is incident on the beam expander 45. The laser beam LBa adjusted to a predetermined beam diameter by the beam expander 45 is split into, for example, eight laser beams LBb by the beam splitter 47 (not shown in FIG. 1). The eight divided laser beams LBb are respectively condensed by a condenser lens 49 and a corner mirror 51 to obtain an acousto-optic modulator (AOM).
The light enters the crystal in the acousto-optic modulator 53 at the same time as being incident parallel to the light 53, and a drawing control unit 102 described later
Are independently modulated based on the raster data by the control signal from the CPU.

The laser beam LBc modulated by the acousto-optic modulator 53 is reflected by a corner mirror 55 and enters a relay lens system 57. The laser beam LBc emitted from the relay lens system 57 is guided to the polygon mirror 67 via the cylindrical lens 59, the corner mirror 61, the spherical lens 63, and the corner mirror 65. Then, a linear spot long in the main scanning direction (x direction) is formed on each surface of the polygon mirror 67.

The linear laser beam LBc that has been deflected and scanned in the horizontal plane by the rotation of the polygon mirror 67 corresponding to the deflecting means of the present invention passes through the fθ lens 68, and then is turned back in the main scanning direction. Is folded downward. After being corrected by the field lens 71 so that the angle of incidence on the exposure surface becomes substantially vertical, the light is irradiated toward the mounting table 15 through the cylindrical lens 73. Cylindrical lens 7
Numeral 3 is long in the main scanning direction and has power only in the sub-scanning direction.

The linear spot on the polygon mirror 67 is divided into an fθ lens 68, a field lens 71,
The laser beam LB (maximum 8) moves in the main scanning direction (x direction) by rotating the polygon mirror 67 by forming a spot having a predetermined diameter on the mounting table 15 by the action with the cylindrical lens 73. Consisting of two laser beams).

The mirror surface and the image forming surface of the polygon mirror 67 have an optically conjugate positional relationship in the sub-scanning direction by the fθ lens 68, the field lens 71, and the cylindrical lens 73. The scanning position shift of the laser beam due to the tilting of the mirror surface from the vertical axis due to the processing error of each mirror surface is corrected.

A mirror 77 for guiding a laser beam to a start sensor 75 is provided between the field lens 71 and the cylindrical lens 73 as shown in FIG. More specifically, the mirror 77 is attached in a state of being suspended from the lower part of the field lens holder 71 a holding the field lens 71, and the start sensor 75 is provided with the laser beam passing through the field lens 71. It is configured so as to be guided obliquely upward.

Here, the start sensor 75 will be described with reference to FIG. FIG. 7A is a perspective view showing a configuration of a start sensor, and FIG. 7B is a diagram showing a waveform detected by the start sensor. As shown in FIG. 7 (a), on the light receiving surface 75a of the start sensor 75, two sensor portions 76a and 76b for receiving a laser beam and a light shielding portion 76c sandwiched between these sensor portions 76a and 76b are provided. Is formed. The width of the sensor portions 76a and 76b in the x direction through which the laser beam passes is, for example, formed larger than the spot diameter (20 μm) of the laser beam, and the width of the light shielding portion 76c in the x direction is, for example, 5 μm. ing. The laser beam is transmitted from the sensor section 76a to the light shielding section 76.
The light is incident on the sensor part 76b in order through c. At this time, each of the sensor units 76a and 76b outputs a voltage waveform as shown in FIG. The start sensor 75 detects the cross point Pc of the voltage waveform and generates a scan start signal a. In this manner, the scanning start signal a can be generated stably with high accuracy by making it less susceptible to fluctuations in the light amount of the laser beam.
The scanning start signal a output from the start sensor 75 is
This is given to a drawing control unit 102 described later, and drawing is started after a predetermined time from that point.

The cylindrical lens 73 has a cylindrical surface facing upward, and has a cylindrical lens holder 73a.
Attached to this cylindrical lens holder 7
3a is fitted into a U-shaped cylindrical lens plate 73b in a plan view, and is attached to the cylindrical lens plate 73b at both ends (FIG. 5). On the base plate 79, position correcting mechanisms 81 for moving the cylindrical lens plate 73b in the sub scanning direction are provided at both ends of the cylindrical lens plate 73b.

The position correcting mechanism 81 will be described. A guide rail 83 is provided on the base plate 79, and a movable table 85 is attached to the guide rail 83 so as to be slidable in the sub-scanning direction. On the extension of the guide rail 83, a stepping motor 87 is provided. By driving the stepping motor 87, the movable table 85 slides on the guide rail 83 and moves in the sub-scanning direction with respect to the base plate 79. It moves (shown by a two-dot chain line in FIG. 5).

By the way, when the position correcting mechanisms 81 provided at both ends of the base plate 79 are independently operated with different drive amounts, particularly when driven in opposite directions, both ends of the cylindrical lens plate 73b are Will move so as to draw an arc in a plan view.
(Approximately 0.5 mm), so that even if an arc is drawn at the time of movement, the “gap” between the guide rail 83 and the moving table 85
It can be absorbed by. It should be noted that a mechanism for positively absorbing, instead of absorbing at the gap, may be provided near both ends.

A detector 91 is provided on the imaging optical system 21 side of the stage base 10 provided at the lowermost layer of the drawing stage 5.
Are arranged side by side in the main scanning direction. Each detector 9
1 includes an arm 93 erected from the stage base 10 toward the processing position PY, and a drawing reference position sensor 95 provided above the arm 93. The arm 93 causes the drawing reference position sensor 95 to be at a height position substantially the same as the height position of the mounting table 15.

FIG. 8 shows the configuration of the drawing reference position sensor 95.
Shown in The drawing reference position sensor 95 is connected to the light receiving surface 9.
This is a sensor capable of detecting the position of the laser beam irradiated to 5a in the main scanning direction and the sub-scanning direction. As the drawing reference position sensor 95, for example, a CCD type two-dimensional image sensor in which a pixel part 95b is two-dimensionally arranged on a light receiving surface 95a is used. When the drawing stage 5 is at the standby position, the two drawing reference position sensors 95 have their center portions in the y direction at the processing position PY, and the start sensor 7
The drawing reference position sensor 95 closer to 5 has its center portion in the x direction positioned at the drawing reference position PX, and the start sensor 7.
The drawing reference position sensor 95 (see FIG. 1) farther from the arm 5 is disposed above the arm 93 so that the center in the x direction is located at the drawing end position PXend.

As shown in FIG. 8, when the laser beam LB is normally scanned at the processing position PY without shifting in the sub-scanning direction, the spot LBs moves straight on the processing position PY. Go. On the other hand, when the laser beam LB is shifted in the sub-scanning direction due to a temperature change or the like, for example, the spot LBs is shifted from the position indicated by the dotted line in FIG. 8, that is, from the processing position PY which is the reference position. The position is shifted toward the imaging optical system 21 by the distance Δd. The drawing reference position sensor 95 can determine the displacement Δd of the spot LBs of the laser beam LB. In this embodiment, the spot LB
As s moves straight on the processing position PY,
The cylindrical lens 73 is moved via the above-described position correcting mechanism 81 to hold the position of the laser beam at the processing position PY, which is the reference position.

Since these drawing reference position sensors 95 are configured such that the pixel portions 95b are two-dimensionally arranged on the light receiving surface 95a, the laser beam can be detected at any position on the light receiving surface 95a. However, as shown in FIG. 1, the drawing reference position PX is used as a laser beam detection position, and when the drawing reference position PX is irradiated with a laser beam, this is detected and a drawing reference position signal h is output, and the drawing ends. The position PXend is set to the laser beam irradiation end position. When the laser beam is irradiated to the drawing end position PXend, this is detected and a drawing end position signal h 'is output. By outputting the drawing reference position signal h and the drawing end position signal h 'to the main controller 121 described later, the drawing effective range of the laser beam is specified. The drawing reference position signal h indicates the barycentric coordinate value of the beam spot obtained by processing the image signal from the image sensor and the spot light amount value. Beam position,
The shift amount is calculated by the drawing control unit 102 based on the barycentric coordinate value and the spot light amount value.

Further, the detection unit 91 is irradiated with a plurality of laser beams in order, compares the output of the drawing reference position sensor 95, feeds back the result to the acousto-optic modulator 53, and outputs the light amounts of all the beams. May be used to make the same. Thereby, even if drawing is performed by a plurality of laser beams, uniform processing can be performed.

Next, the data processing unit 101 and the drawing control unit 1
02 will be described with reference to FIG. FIG. 9 is a block diagram illustrating a schematic configuration of a printed wiring board manufacturing apparatus. The data processing unit 101 receives artwork data of a printed wiring board designed using CAD and converts the artwork data into run-length data for raster scan drawing. As the data processing unit 101, for example, a workstation or a personal computer is used.

The drawing control unit 102 includes a displacement calculating unit 89
, An alignment data calculation unit 111, a run length data buffer 112, a raster conversion circuit 113, a drawing data buffer memory 114, and a drawing processing unit 115.

As shown in FIG. 1, a reference scale having a length scale for measuring the irradiation position of the laser beam is provided on the side of the mounting table 15 on which the printed wiring board S is mounted, near the detecting section 91. Reference numeral 88 is provided in the main scanning direction (x direction). Before laser drawing on the printed wiring board S,
Laser beam in main scanning direction with respect to reference scale 88
Irradiation is performed at intervals of 10 mm, and a spot of the irradiated laser beam and a length scale of a reference scale 88 on which the spot is located are imaged by a CCD camera (not shown), and a positional deviation calculating unit is used as irradiation position data. 89
(See FIG. 9), and the irradiation position of the laser beam at every 10 mm interval is measured in advance. Positional displacement calculator 89
Based on the irradiation position data of the laser beam measured by the CCD camera, the position shift correction data for correcting the position shift of the laser beam, that is, for making the drawing pitch by the laser beam constant, is provided. Then, the calculated misregistration correction data is output to the main controller 121 of the drawing processing unit 115. Note that the position shift correction data is a phase increase set value (frequency set value) k set in a position shift correction memory 131 described later.

The alignment data calculator 111 includes CCDs for the respective alignment scopes 33, 35, 37, and 39.
The cameras 33a, 35a, 37a, 39a are all connected. The alignment data calculation unit 111 is provided for each CCD.
Each video signal collected from the cameras 33a, 35a, 37a, and 39a is arithmetically processed to reduce the magnification of the printed wiring board S and the magnification correction ratio j (magnification correction data) according to the dimensional change of the printed wiring board S. ) Is obtained, and the obtained posture shift and the reduction ratio j are output to the main controller 121 of the drawing processing unit 115. Main controller 121
Corrects the phase increase set value (frequency set value) k according to the scaling correction rate j from the alignment data calculation unit 111.

The above-described alignment scope unit 31 and alignment data calculation unit 111 correspond to the expansion / contraction amount detecting means in the present invention, and the main controller 121 corrects the displacement correction data according to the expansion / contraction amount in the present invention. It corresponds to a means.

The run-length data buffer 112 temporarily stores all the run-length data converted by the data processing unit 101. The raster conversion circuit 113 converts the sequentially read run-length data into raster data in pixel units. The drawing data buffer memory 114 stores raster data for each scan. Drawing processing unit 115
Gives a raster conversion instruction to the raster conversion circuit 113, reads out the raster data stored in the drawing data buffer memory 114 with a drawing clock signal f from a drawing clock generating circuit 123, which will be described later, and reads the raster data.
Output to The acousto-optic modulator 53 modulates the laser beam based on the drawing signal generated by the read raster data.

The drawing processing unit 115 includes a main controller 121, a reference clock generation unit 122, a drawing clock generation circuit 123, a polygon rotation control unit 124,
And a Y-axis synchronization control unit 125.

The main controller 121 includes a phase increase set value k as the position shift correction data calculated by the position shift calculator 89 and the alignment data calculator 111.
Of the posture of the printed wiring board S and the reduction ratio j obtained by
, A scan start signal a detected by the start sensor 75 for each scan, a drawing reference position signal h detected by the drawing reference position sensor 95, a polygon surface detector 126.
(A signal indicating the surface of the polygon mirror 67 irradiated with the laser beam) and the like. The main controller 121 controls the drawing clock generation circuit 12 based on the phase increment set value k from the displacement calculator 89.
3 and the position correcting mechanism 81 according to the posture deviation of the printed wiring board S from the alignment data calculation unit 111.
To correct the phase increase set value k in accordance with the scaling correction rate j of the printed wiring board S from the alignment data calculation unit 111, and control the polygon rotation control unit 124 and the Y-axis synchronization control unit 125. .

The polygon surface detector 126 detects the surface of the polygon mirror 67 irradiated with the laser beam. This polygon surface detector 126
For example, the mark formed on the polygon mirror 67 is optically detected to detect the first surface of the polygon mirror 67, and the remaining second to n-th surfaces of the polygon mirror 67 are shown in FIG. As described above, the scanning start signal a from the start sensor 75 is detected by counting by the counter unit 126a.

The reference clock generator 122 is composed of a crystal oscillator or the like, generates a reference clock signal b, and outputs it to the drawing clock generator 123. As shown in FIG. 9, the polygon rotation control unit 124 controls the rotation of the polygon mirror 67 in accordance with an instruction from the main controller 121. The Y-axis synchronization control unit 125 drives and controls the drawing stage 5 in the y-axis direction in synchronization with laser drawing according to an instruction from the main controller 121.

The drawing clock generating circuit 123 is provided for each laser beam as shown in FIG. FIG.
0 is a block diagram showing a configuration of a main part of the drawing control unit. These drawing clock generation circuits 123 include a position shift correction memory 131, a direct digital synthesizer (hereinafter abbreviated as DDS) 132, and a frequency multiplication circuit 1.
33 and a synchronization processing unit 134. Note that the main controller 121 is provided with a displacement calculating unit 89.
The set value (frequency set value) k of the phase increment from the above is set in the displacement correction memory 131. Here, the phase increment set value k is for setting the frequency of the drawing clock signal f output from the drawing clock generating circuit 123, as will be clear from the description below. The misalignment correction memory 131 stores and holds a phase increase set value k set by the main controller 121. DDS1
Reference numeral 32 denotes a reference clock signal b at a correction position among the reference clock signals b for one scanning line from the reference clock generation unit 122, according to the phase increment set value k read from the displacement correction memory 131. , And output after adjusting to a desired frequency. The frequency multiplying circuit 133 multiplies, for example, four times the reference clock signal c adjusted by the DDS 132 and outputs the multiplied signal. The synchronization processing unit 134 includes a frequency multiplier 133
The reference clock signal d multiplied by 4 by the start sensor 7
5 is output as a drawing clock signal f in synchronization with the scanning start signal a from the reference numeral 5.

As described above, each drawing clock generating circuit 123
The raster data for each laser beam is read out from the drawing data buffer memory 114 in accordance with the drawing clock signal f for each laser beam adjusted in the above step, and the corresponding laser beams are respectively modulated and modulated based on the drawing signal. Each of the laser beams is applied to the printed wiring board S, and a drawing pattern corrected for positional deviation is formed on the printed wiring board S.

The above-described drawing clock generation circuit 12
3 corresponds to a signal adjusting means in the present invention, the above-described displacement correction memory 131 corresponds to a memory unit in the present invention, and the frequency multiplying circuit 133 and the synchronization processing unit 1 described above.
Reference numeral 34 corresponds to the multiplying means in the present invention.

Here, the DDS 132 will be described more specifically. The DDS 132 is an arbitrary frequency generator that creates an oscillation waveform to be output by synthesizing it with digital data of a sine waveform stored in advance. This DDS 132 is, as shown in FIG.
For example, an address calculator (phase accumulator) 141
, A Sin (sine) waveform memory 142, a D / A (digital-analog) converter 143, and a low-pass filter (LPF) 144. The address calculator 141 includes an N-bit full adder 141a and a register 141b. A reference clock signal (system clock) b whose frequency is Fs from the reference clock generation unit 122 is trigger-input to the register 141b and the D / A converter 143. Sin waveform memory 14
2, digital data of a Sin (sine) waveform is stored in advance. When the phase increment set value k is input to the N-bit full adder 141a, the read address 1 is output from the register 141b to the Sin waveform memory 142. This read address 1 is an N-bit full adder 1
The read-out address 1 is fed back to the read-out address l, and the phase increment set value k is added to the read-out address l. A discrete sine wave is output from the sine waveform memory 142 in accordance with the read address 1 set at intervals for each phase increment set value k, and the D / A converter 143 converts the discrete sine wave into an analog signal. The frequency clock component is cut by the LPF 144, and the reference clock signal c whose frequency is adjusted to Fg is output. Although the reference clock signal c is a sine wave, if a rectangular wave is required, it may be converted to a rectangular wave using a comparator or the like.

When the address calculator 141 and the displacement correction memory 131 are composed of N bits, the frequency Fs of the reference clock signal b and the frequency Fg of the reference clock signal c to be output are calculated by the following equation. It has the relationship of (1). Fg (output frequency) = Fs (reference clock signal) × k (increase in phase) / 2 ^N (1) Therefore, 1/2 of the frequency Fs of the reference clock signal b
The frequency can be switched with a frequency resolution of ^N.
For example, the address calculator 141 and the displacement correction memory 1
31 and 32 bits, the frequency Fs of the reference clock signal b is 104.8576 MHz, and the frequency Fg of the reference clock signal c to be output is 16 MHz, and the phase increase set value k set in the displacement correction memory 131 is 16 MHz × 2 ³² /104.8576 MH in accordance with the above-mentioned equation (1).
z = 655360000. The frequency resolution is 16MHz /
655360000 ≒ 0.025 Hz, frequency multiplier 133
, The resolution is 0.025 Hz × 4 = 0.100 Hz. Here, the frequency of the drawing clock signal f is 6
4 MHz, scan width 410 mm, misalignment correction interval 10 m
When one clock of the drawing clock signal corresponds to the pixel pitch of 5 μm, the misalignment correction memory 1
31 is set to “655360000 + 1”
”, The frequency increases, the output of the DDS 132 becomes approximately 16.000000025 MHz, and the frequency multiplication circuit 13
It is multiplied by 4 by 3 to be about 64.000000100 MHz. Therefore, since 0.0000001 MHz / 64 MHz0.10.15 / 100 million, 0.15 / 0.15 (0.15 pp
m) It is possible to perform correction in units. If this is replaced with a displacement correction dimension, a correction of about 0.015 nm can be performed for 10 mm, and the correction amount is uniformly applied during the scanning of 10 mm. Position shift correction can be realized.

Actually, a fourth-order polynomial representing the scanning speed distribution of the fθ lens 68 is obtained from the irradiation position data obtained by measuring the irradiation position of the laser beam irradiated at intervals of 10 mm, and this is integrated to indicate the scanning position. A fifth-order polynomial approximation is obtained. Based on this fifth-order polynomial approximation, a unit of 16 pixels (16 × 5 =
The position shift correction data of 80 μm), that is, the phase increase set value k in units of 16 pixels is calculated, and the phase increase set value k in units of 16 pixels is set in the position shift correction memory 131. Specifically, the scanning width is 410 mm, and 410 mm /
Since 80 μm = 5125, the set value k of the phase increase in units of 16 pixels for 5125 is set in the correction memory 131. Similarly to the above, when the frequency of the drawing clock signal f is 64 MHz, one clock of the drawing clock signal f has a pixel pitch of 5 μm, and the misregistration correction interval is 80 μm, 0.15 / 0.15 (0.15 pp
m) It is possible to perform correction in units. Therefore, if this is replaced with a displacement correction dimension, 80 × 10 ⁻⁶ mm × 0.15 ×
Since 10 ^-8 = 0.12 pm, 0.12 p for 80 μm
Correction in units of m becomes possible, and the amount of correction is uniformly applied during the scanning of 80 μm, so that high-accuracy and high-resolution positional deviation correction can be realized.

Here, a multi-beam configuration in this embodiment will be described. FIG. 12 is a diagram showing a drawing coordinate system in this embodiment. FIG. 13A is a diagram showing a multi-beam array and its beam interval.
(B) is a diagram showing a drawing vector. In order to eliminate the mutual interference of the laser beams, the multi-beams are arranged so as to be oblique to the scanning lines as shown in FIG. That is, as shown in FIG. 13A, the distance between adjacent beams in the main scanning direction (x direction) is about 100 μm, and the distance between adjacent beams in the sub scanning direction (y direction) is a pixel unit of raster drawing. It is adjusted to be several μm. Therefore, ch (channel) 1 to 8 beams
The distance between the beam centers of ch8 is about 700 μ in the x direction.
The interval in the m and y directions is 35 μm.

Further, since the drawing stage is continuously driven in the sub-scanning direction by 40 μm while the multi-beam scans one time in the main scanning direction, drawing is performed. Therefore, as shown in FIGS. Is inclined with respect to the x-axis so that the line in the x-direction and the line in the y-direction are at a right angle when the rectangular pattern is drawn on the substrate. Assuming that the scanning line inclination angle θ is an effective drawing width of 410 mm and an effective scanning efficiency (a ratio of an effective drawing time to one scanning time (start pulse period)) of 50%, the following equation (2) is used.
Required from. θ = tan ⁻¹ ｛(40 μm / 410 mm) × 0.5｝ ≒ tan ⁻¹ (4.878 × 10 ^-5 ) (2) A cylindrical lens is formed so that θ obtained by the equation (2) is obtained. 73 is tilted for adjustment.

Subsequently, in the printed wiring board manufacturing apparatus of the embodiment having the above configuration, the above-described first to third correction examples will be sequentially described. <First Correction Example> Here, the operation (first correction function) of correcting the positional deviation of the drawing pattern due to the distortion of the scanning optical system in the printed wiring board manufacturing apparatus of the embodiment having the above configuration will be described.

Before starting the laser drawing on the printed wiring board S, the calculation and setting of the phase increment set value k as the displacement correction data are performed as follows. First, as shown in FIG.
The drawing stage 5 is moved so as to be positioned at Y.
Move the laser beam in the main scanning direction with respect to the reference scale 88.
Irradiation is performed sequentially at intervals of 10 mm, and the spot of the irradiated laser beam and the length scale of the reference scale 88 where the spot is located are imaged by a CCD camera and output to the displacement calculator 89 as irradiation position data ( (See FIG. 9). The displacement calculator 89 obtains the beam center of gravity from the multi-level light amount distribution of the spot, and calculates the position corresponding to the beam center of gravity as the irradiation position of the laser beam. In this way, the irradiation position of the laser beam at every 10 mm interval is calculated in advance. Further, the displacement calculator 89 performs phase increase as displacement correction data for correcting the displacement of the laser beam based on the irradiation position data of the laser beam so that the drawing pitch by the laser beam is constant. The minute set value k is calculated. Specifically, 10mm
From the irradiation position data of the laser beam measured at each interval, a fourth-order polynomial that indicates the scanning speed distribution of the fθ lens 68 is obtained, and this is integrated to obtain a fifth-order polynomial approximation that indicates the scanning position. Based on the polynomial approximation formula, the set value k of the phase increment for every 16 pixels is set to 5125 (scan width 410 mm /
It is calculated over 16 pixels 80 μm = 5125). The misregistration calculation unit 89 calculates the phase increase set value k of 16 pixels in units of 5125 pixels calculated as described above in the main controller 12.
Output to 1. The main controller 121
The set value k of the phase increment in units of 16 pixels is set in the displacement correction memory 131.

The drawing clock generation circuit 123 reads out the set values k of the phase increments of 16 pixels in units of 5125 set in the displacement correction memory 131 in order of address, and outputs the reference clock signal b from the reference clock generation unit 122. The frequency is adjusted to a desired frequency according to the read phase increment set value k in units of 16 pixels, and is output after being multiplied by four. In this way, the drawing clock signal f for one scan line sequentially adjusted to a desired frequency is output in accordance with the set value k of the phase increase amount in units of 16 pixels of 5125 pieces.
This drawing clock generation circuit 123 sets the phase increase set value k.
Raster data is read out with the drawing clock signal f adjusted according to. The acousto-optic modulator 53 modulates the laser beam based on the drawing signal. The modulated laser beam is irradiated on the printed wiring board S, and a drawing pattern is formed on the printed wiring board S. The drawing pattern is, as shown in FIG.
The position shift is corrected in accordance with the phase increase set value kc after the correction from. FIG. 14A is a diagram showing a portion where the displacement of the drawing pattern is caused by the distortion of the scanning optical system, and FIG. 14B is a diagram showing the position displacement of the drawing pattern shown in FIG. It is the figure which corrected.

Due to the distortion of the scanning optical system, the drawing pattern is displaced as shown in FIG. 14A, that is, the drawing size of the drawing pattern fluctuates. This displacement of the drawing pattern is caused by the fact that the main scanning speed of the laser beam during one scanning period of the laser beam is not constant, as shown in FIG. The main scanning speed at the end of one scanning period of the laser beam is higher than, for example, at the center of one scanning period. In FIG. 14A,
Shows a drawing pattern P ₁ at the end of one scanning period of the laser beam. As shown in FIG. 14A, the uncorrected phase increase set value of the DDS 132 at this time is ki.
, DDS 132 is assumed to be Fi, and this output frequency Fi is quadrupled by the frequency multiplier 133 to output a drawing clock signal f having a frequency fi (fi = Fi × 4). Frequency raster data of the drawing data buffer memory 114 at writing clock signal f fi are read out, drawing signal is output to the acousto-optic modulator 53, the drawing pattern P ₁ is formed on the printed circuit board S. Drawing size S ₁ of the drawing pattern P ₁ is,
As described above, since the main scanning speed at the end of one scanning period of the laser beam is faster than the main scanning speed of the laser beam at the center thereof, the reference drawing size S _{0 is used.}
It will be formed larger. This can be understood from the following description. If the main scanning speed of the laser beam is constant, as shown in FIG.
Although it will be drawn with pixels arranged at equal intervals and uniformly, since the main scanning speed of the laser beam is not constant,
As shown in FIG. 15A as an actual drawing position, drawing is performed with pixels having uneven spacing and non-uniformly arranged, resulting in uneven drawing positions.

Therefore, in the present embodiment, FIG.
As shown in (5), the position shift correction is executed based on the corrected phase increase set value kc from the position shift calculator 89. The drawing clock generating circuit 123 is provided with the displacement calculating unit 8.
The drawing clock signal f at the correction location is adjusted to a desired frequency in accordance with the corrected phase increment set value kc from step 9.
More specifically, the drawing clock generation circuit 123 sets the corrected phase increase set value kc from the displacement calculator 89 in the displacement correction memory 131. The DDS 132 outputs the reference clock signal c of Fc having a frequency higher than the uncorrected Fi to the frequency multiplying circuit 133 in accordance with the phase increase set value kc set in the displacement correction memory 131. The frequency multiplying circuit 133 multiplies the reference clock signal c having a frequency of Fc by four to obtain the uncorrected frequency f.
A drawing clock signal f of fc (fc = Fc × 4) higher in frequency than i is output to the drawing data buffer memory 114. Frequency raster data of the drawing data buffer memory 114 at writing clock signal f fc is read, rendering the signal is output to the acousto-optic modulator 53, drawing size S ₀ to shrink corrected drawing pattern P as a reference ₀ is formed on the printed wiring board S.

As described above, the drawing clock generation circuit 123
Can adjust the drawing clock signal f at the correction location among the drawing clock signals f for one scanning line to a desired frequency in accordance with the phase increment set value k. It is possible to adjust the drawing pitch by the laser beam so as to be constant without using a plurality of types of clocks having different phases, so that the configuration for generating the plurality of types of clocks is unnecessary, and the scanning optics can be simplified with a simple configuration. It is possible to correct the displacement of the drawing pattern due to system distortion with high accuracy. Specifically, by adjusting the frequency of the drawing clock signal f in one scanning period as shown in FIG. 15C, the drawing pitch by the laser beam can be made constant as shown in FIG. As shown by the broken line in FIG. 15A, it is possible to correct the scanning optical characteristic to an ideal linear constant speed, and to draw a drawing pattern on the printed wiring board S by pixels arranged at equal intervals and evenly. Can draw.

The drawing clock generating circuit 123 includes a displacement correction memory 131, a DDS 132, a frequency multiplying circuit 133, and a synchronization processing section 134. The misregistration correction memory 131 holds, as misregistration correction data, a set value k (frequency setting value) of the phase increase of the drawing clock signal f at the correction location among the drawing clock signals f for one scanning line. Position shift correction memory 1
A clock having a desired frequency adjusted according to the phase increment set value k from 31 is generated.
The clock from the DS 132 is multiplied and the synchronization processing unit 13
Numeral 4 outputs a clock multiplied by the frequency multiplying circuit 133 as a drawing clock. Therefore, it is possible to set the frequency of the drawing clock signal f at the correction location among the drawing clock signals f for one scanning line with high resolution.
It is possible to realize a configuration in which the displacement of the drawing pattern is corrected with high accuracy in minute units of one pixel or less of the raster data.

The main scanning speed characteristics of each laser beam in multi-beam writing show the same tendency. For example, as shown in FIG. 19A, the main scanning speed characteristic of the CH2 laser beam is different from the main scanning speed characteristic of the CH1 laser beam by Δtm time. The Δtm time corresponds to a value obtained by converting the beam CH interval in the main scanning direction between CH1 and CH2 into time. Therefore, the correction characteristic of the drawing clock signal f of CH2 may be handled as a correction characteristic of the drawing clock signal f of CH1 shifted by Δtm time as shown in FIG. 19B. The remaining laser beams CH3 to CH8 may be handled in the same manner as described above. Therefore, as shown in FIG. 10, the configuration for correcting the positional deviation of the drawing pattern of each beam in the multi-beam writing with high accuracy includes a single reference clock generation unit 122, a writing clock generation circuit 123 for each beam, and And can be made compact.

In the first correction example, as described above, the CCD camera, the reference scale 88, and the displacement calculating section 8
9 is used to calculate the phase increase set value k as the displacement correction data, but it may be calculated as follows. For example, a grid-like drawing pattern is applied to a glass dry plate on which a photosensitive material is adhered or a printed wiring board for calibration.
After drawing at grid intervals and developing the grid-like drawing pattern, each intersection point of the grid-like drawing pattern was actually measured.
Fθ lens 6 from actual measurement data at each intersection at 10 mm intervals
Then, a fourth-order polynomial representing the scanning speed distribution of No. 8 is obtained, and this is integrated to obtain a fifth-order polynomial approximation indicating the scanning position.
Based on the following polynomial approximation, a phase increase set value k in units of 16 pixels is calculated so that the scanning speed of the laser beam is constant.

<Second Correction Example> Next, among the distortions of the scanning optical system described in the first correction example, in particular, the rotational accuracy of the polygon mirror 67 and the positional deviation of the drawing pattern due to the uneven rotation of each surface. (Second correction function) will be described.

The apparatus of this embodiment detects the scanning speed distribution of the laser beam for each surface of the polygon mirror 67 in order to correct the rotational accuracy of the polygon mirror 67 and the positional deviation of the drawing pattern due to the uneven rotation of each surface. Scale 88, a CCD camera, a start sensor 75, a drawing reference position sensor 95, a polygon surface detector 126, and a polygon mirror 67 so that the detected drawing pitch of each surface of the polygon mirror 67 by the laser beam is constant. A position shift calculator 89 for calculating a phase increase set value k (frequency set value) as position shift correction data for each surface, and a phase increase setting as position shift correction data for each surface of the polygon mirror 67. A misalignment correction memory 131 for storing a value k (frequency setting value).

The reference scale 88, the CCD camera, the start sensor 75, the drawing reference position sensor 95, and the polygon surface detector 126 correspond to the scanning speed distribution detecting means in the present invention, and the displacement calculating section 89 corresponds to the present invention. Corresponds to the calculating means for calculating the displacement data for each surface of the polygon mirror, and the displacement correction memory 131 corresponds to the storage means in the present invention.

Next, a description will be given of the operation of the apparatus of this embodiment for correcting the rotational accuracy of the polygon mirror 67 and the displacement of the drawing pattern due to the uneven rotation of each surface.

For example, when the rotation center of the polygon mirror 67 is deviated or there is uneven rotation, the polygon mirror 6
If the rotation accuracy of the polygon mirror 7 is equal to or less than a specified value, or if the angle of the polygon surface of the polygon mirror 67 varies from surface to surface, and an angle error occurs for each polygon surface of the polygon mirror 67, the polygon mirror The unevenness (error) occurs in the scanning speed of the laser beam for each surface 67, that is, the scanning speed of the laser beam varies for each polygon surface. The fluctuation of the scanning speed for each polygon surface causes deterioration of the drawing quality. Here, calibration is performed in such a case.

Before starting the laser drawing on the printed wiring board S, detection of the scanning speed distribution of the laser beam for each surface of the polygon mirror 67 and each of the polygon mirrors 67 corresponding to the detected scanning speed distribution are performed. The calculation of the position shift correction data (phase increase set value k) for each surface and the setting of these in the position shift correction memory 131 are performed in advance as follows.

First, as shown in FIG. 1, the drawing stage 5 is moved to the standby position so that the center of the drawing reference position sensor 95 in the y direction is located at the processing position PY. As shown in FIG. 9, the start sensor 75 detects the irradiation of the laser beam and outputs a scan start signal a to the main controller 121. In this way, the start of scanning of the laser beam in the main scanning direction is detected. The laser beam detected by the start sensor 75 is deflected in the main scanning direction and is sequentially irradiated on the two drawing reference position sensors 95. The drawing reference position sensor 95 closer to the start sensor 75 detects the irradiation of the laser beam to the drawing reference position PX (see FIG. 1) and outputs a drawing reference position signal h to the main controller 121. The drawing reference position sensor 95 farther from the start sensor 75 detects the drawing end position P
A laser beam irradiation to Xend (see FIG. 1) is detected, and a drawing end position signal h 'is output to the main controller 121. The main controller 121 calculates the beam spot based on the coordinate value of the beam spot obtained from the drawing reference position signal h.
A time difference from the detection of the scanning start signal a to the detection of the drawing reference position signal h is calculated, and a period from the detection of the drawing reference position signal h to the detection of the drawing end position signal h ′ is defined as a scanning effective period. The period other than the above is calculated as the scan invalid period. Here, the scan invalid period is a period during which the laser beam cannot be irradiated on the printed circuit board S, and the scan effective period is a period during which the laser beam can be irradiated on the printed circuit board S.

Next, the drawing stage 5 is moved so that the reference scale 88 is located at the processing position PY. The scanning speed distribution of the laser beam for each surface of the polygon mirror 67 is detected by the reference scale 88, the CCD camera, the start sensor 75, and the polygon surface detector 126. Specifically, the main controller 121 detects the first surface of the polygon mirror 67 based on the surface signal i from the polygon surface detector 126 as shown in FIG. Beam to reference scale 88
The rotation of the polygon mirror 67 is controlled so as to sequentially irradiate from the drawing reference position to the drawing end position in the main scanning direction at intervals of 10 mm, and the spot of the irradiated laser beam and the spot are located. The length scale of the reference scale 88 is controlled to be imaged by the CCD camera. These video signals imaged for the first surface of the polygon mirror 67 are output to the displacement calculating unit 89 as irradiation position data. The displacement calculator 89 calculates the irradiation position of the laser beam at intervals of 10 mm based on the video signal. Specifically, the beam center of gravity is determined from the multi-level light quantity distribution of the spot of the laser beam, and the position corresponding to the beam center of gravity is calculated as the irradiation position of the laser beam. Thus, the scanning speed distribution of the laser beam on the first surface of the polygon mirror 67 is detected. The video signals for the remaining second to n-th surfaces of the polygon mirror 67 are also output to the displacement calculator 89 in the same manner as described above, and the laser beams of the second to n-th surfaces of the polygon mirror 67 are output. A scanning speed distribution is detected.

The displacement calculator 89 includes a polygon mirror 6
7 so that the drawing pitch of the laser beam on all surfaces (first to n-th surfaces) of the polygon mirror 7 is constant.
Based on the irradiation position data of the laser beam on all the surfaces of the polygon mirror 67, the phase increase set value k for each surface of the polygon mirror 67 for correcting the positional deviation of the laser beam is calculated. Specifically, the fθ lens 68 is obtained from the irradiation position data of the laser beam measured at intervals of 10 mm as described above.
A fourth-order polynomial showing the scanning speed distribution of is obtained for each surface,
These are integrated to obtain a fifth-order polynomial approximation that indicates the scanning position for each surface. From these fifth-order polynomial approximations, the drawing pitch of the laser beam on all surfaces of the polygon mirror 67 becomes constant. 5125 (scanning width 410 mm / 16 pixels 80 μm = 51) for each surface of the polygon mirror 67
25) is calculated for each 16 pixels. The displacement calculating unit 89 outputs the phase increase setting value k of 5125 pixels for each surface of the polygon mirror 67 calculated in the above-described manner to the main controller 121 in units of 16 pixels.

As shown in FIG. 16, the main controller 121 performs 5125 operations for each surface of the polygon mirror 67.
Phase increase setting values k (k _{0 to} k
_end ) is set in the displacement correction memory 131. The misalignment correction memory 131 is provided with 5125 recording areas divided by memory addresses from “0” to “end” for each of the first to n-th surfaces of the polygon mirror 67. In each of the recording areas over n * 5125, the set value k of the phase increment for each 16 pixels calculated as described above is set. However, in the recording area where the memory address is “end”, an initial value on the next surface of the polygon mirror 67 (a phase increment set value k _{end in} 16-pixel units to be used first on the next surface of the polygon mirror 67) Is recorded.

As described above, the phase increase setting value k for each surface of the polygon mirror 67 in the displacement correction memory 131
After the setting of (k _{0 to} k _end ) is completed, the laser drawing on the printed wiring board S is started.

Next, the operation of laser writing on the printed wiring board S will be described. As shown in FIG. 17, the main controller 121 specifies a surface to be irradiated with a laser beam from among the surfaces of the polygon mirror 67 based on the surface signal i from the polygon surface detector 126. The main controller 121 sets the phase increment set value k in units of 16 pixels recorded in the recording area of the memory address “end” on the surface before the specified surface.
_end at least, and then the memory address “0”,
In the order of “1”, “2”,..., The phase increment set value k (k ₀ ,
k _1, k _2, controls the position deviation correction memory 131 to output the DDS132 reads ...). It should be noted that these phase increment setting values k _{0 to} k in units of 16 pixels
_{The end} of the drawing clock signal f is synchronized with the scanning start signal a.
According to the read clock signal e generated every 16 clocks, the DDS
132 is set.

The DDS 132 is connected to the reference clock generator 12
2 is transferred to the displacement correction memory 1
In accordance with a set value k (k _{0 to} k _end ) of a 16-pixel unit read from memory 31 in the order of memory addresses, the frequency is sequentially adjusted to f _{0 to} f _end every 16 pixels and output to the frequency multiplier 133. I do. The frequency multiplier 133 has a DD
In step S132, the reference clock signal c adjusted in the order of f _{0 to} f _end for every 16 pixels is, for example, quadrupled and output to the synchronization processing unit 134. The synchronization processing unit 134 outputs the reference clock signal d quadrupled by the frequency multiplication circuit 133.
Is output as a drawing clock signal f in synchronization with the scanning start signal a from the start sensor 75.

Therefore, the drawing clock signal f is
As shown in FIG. 7, the frequency is adjusted to a desired frequency every 16 pixels. The drawing clock signal f is also adjusted on the next surface of the polygon mirror 67 in the same manner as described above. Specifically, on the first surface of the polygon, the frequency is _fend n × 4, f ₀ × 4, f ₁ × 4, f ₂ × 4 every 16 pixels.
, _Fend-1 × 4 The laser beam is modulated with a drawing signal generated by raster data read out with the drawing clock signal f adjusted in the order of _fend-1 × 4, and the modulated laser beam is irradiated. On the second surface of the polygon, the frequency is f _end × 4, f ₀ ′ × 4, f ₁ ′ × 4, f ₂ ′ ×
4,..., F _end-1 ′ × 4 The laser beam is modulated by a drawing signal generated by the raster data read out with the drawing clock signal f adjusted in the order of × 4, and this modulated laser beam is irradiated. Is done. On the polygon n-th surface, the frequency is f _end n-1 × 4, f ₀ n × 4, f ₁ n every 16 pixels.
The laser beam is modulated by a drawing signal generated by raster data read out with the drawing clock signal f adjusted in the order of × 4, f ₂ n × 4,..., F _end-1 n × 4. The modulated laser beam is emitted.

As described above, the polygon mirror 67 is formed by the reference scale 88, the CCD camera, the start sensor 75, the drawing reference position sensor 95, and the polygon surface detector 126.
The main controller 121 detects the scanning speed distribution of the laser beam for each surface of the polygon mirror 67 so that the drawing pitch of the laser beam on each surface of the polygon mirror 67 is constant. According to the scanning speed distribution of the laser beam, a phase increase set value k (k _{0 to} k _end ) for each surface of the polygon mirror 67 is calculated and set in the displacement correction memory 131. The drawing clock signal f is set to 16 in accordance with the phase increase setting value k (k _{0 to} k _end ) for each surface of the polygon mirror 67 set in the displacement correction memory 131.
Since the frequency is adjusted to a desired frequency for each pixel, the drawing pitch of each surface of the polygon mirror 67 by the laser beam can be made constant, and the rotation accuracy of the polygon mirror 67 can be improved.
It is possible to correct the displacement of the drawing pattern due to the rotation unevenness of each surface.

In the second correction example, a start sensor 75, a drawing reference position sensor 95, and a position shift calculating unit are used to correct the rotation accuracy of the polygon mirror 67 and the position shift of the drawing pattern due to the uneven rotation of each surface. 89 and the main controller 121 are used. However, even when a generating means for receiving a reference laser beam different from the drawing laser beam through the polygon mirror 67 and generating a drawing clock signal is provided, It is possible to correct the positional deviation of the drawing pattern due to the rotation accuracy of 67 and the rotation unevenness of each surface, that is, it is possible to cancel the fluctuation of the scanning speed for each polygon surface. In this case, the drawing reference position sensor 95 and
The reference clock generator 122 can be made unnecessary. As shown in FIG. 18, the generating means includes a separating mirror 96 for separating a part of the laser beam from the laser light source 41 as a reference laser beam (reference light), and a beam for supplying the reference light to the polygon mirror 67. A synthesizing unit 97, a grating sensor 98 that receives a reference beam through the polygon mirror 67 and the cylindrical lens 73 and generates a drawing clock signal f ′, and multiplies the drawing clock signal f ′ to generate a reference clock to the DDS 132. A frequency multiplier 99 for generating the signal b. If there is a pitch error in the slit of the grating sensor 98 through which the reference light passes, a drawing clock signal f in which a position shift has occurred due to the pitch error is generated. However, in the embodiment shown in FIG. 18, the drawing clock signal f from the drawing clock generating circuit 123 is transmitted from the position calculating unit 89 to the polygon mirror 67 set in the position correcting memory 131 in the drawing clock generating circuit 123. The frequency is adjusted to a desired frequency in accordance with the set value k of the phase increment for each surface, so that the pitch error can be corrected, the writing clock generation position shift can be corrected, and the writing pattern position shift can be corrected with high accuracy. Can be corrected.

When the multi-beam writing is adopted, a writing clock generating circuit is basically provided for each beam as shown in FIG. What is necessary is just to read out the phase increment set value k from the memory and generate the drawing clock signal of the desired frequency. However, since the frequency of the drawing clock signal f ′ generated by the grating sensor 98 is not constant, it is necessary to adjust the phase increment set value k for each channel according to the frequency.

<Third Correction Example> Subsequently, an operation of correcting the positional shift of the drawing pattern due to the distortion of the scanning optical system and correcting the drawing pattern in accordance with the dimensional change of the printed wiring board S (third correction) Function) will be described.

The apparatus according to this embodiment includes an alignment scope unit 31 for detecting the amount of expansion and contraction of the printed wiring board S in order to reduce the magnification of the drawing pattern in accordance with the dimensional change of the printed wiring board S. An alignment data calculation unit 111 for calculating a magnification reduction ratio j corresponding to a dimensional change of the printed wiring board S and outputting the same to the main controller 121, and for each surface of the polygon mirror 67 calculated by the displacement calculation unit 89. A main controller 121 is provided for correcting a phase increase set value k (frequency set value) as position shift correction data in accordance with a scaling correction rate j from the alignment data calculation unit 111. The apparatus of this embodiment includes a reference scale 88 for detecting a scanning speed distribution of a laser beam for each surface of the polygon mirror 67, a CCD camera, a start sensor 75, and the like, as in the case of the above-described second correction example. The drawing reference position sensor 95, the polygon surface detector 126, and the detected polygon mirror 6
7, a position shift calculator 89 for calculating a phase increase set value k (frequency set value) as position shift correction data for each surface of the polygon mirror 67 so that the drawing pitch of each surface of the polygon mirror 67 with the laser beam is constant. It has.

Next, the operation of the apparatus of this embodiment for correcting the positional deviation of the drawing pattern due to the distortion of the scanning optical system and correcting the drawing pattern in accordance with the dimensional fluctuation of the printed wiring board S will be described. Note that the correction of the displacement of the drawing pattern has been described in the above-described second correction example, and the description thereof will be omitted here.

As shown in FIG. 1, the printed wiring board S is mounted at a reference position on the mounting table 15. Then, before drawing, a dimensional change of the printed wiring board S in the main scanning direction is detected as follows. As shown in FIG. 12, among the positioning holes A at the four corners of the printed wiring board S, for example, two positioning holes A arranged in the main scanning direction closer to the cylindrical lens 73 are connected to the CCD camera 33a,
Read at 35a. Note that the CCD cameras 33a, 35
A, 37a, and 39a may read all four alignment holes A. The alignment data calculation unit 111
Based on the video signals from the CCD cameras 33a and 35a, a distance X between the two alignment holes A in the main scanning direction is determined.
Find 1 The alignment data calculation unit 111 obtains a scaling correction rate j based on the obtained distance X1 and a distance in the main scanning direction of the positioning hole A which is given in advance as a dimension reference. j is output to the main controller 121. The main controller 121 calculates the phase increment set value k (k ₀ to k) for each surface of the polygon mirror 67 in units of 16 pixels calculated by the displacement calculating unit 89.
The k _{en d)} were uniformly corrected according to Chijimibai correction factor j, phase increment of 16 pixels of the corrected amount setting value k × j (k ₀ × j~k
_end × j) is set in the displacement correction memory 131 of the drawing clock generation circuit 123.

The drawing clock generating circuit 123 reads out the corrected phase increment set value k × j (k ₀ × j to k _end × j) in the unit of 16 pixels set in the displacement correction memory 131 in the order of memory addresses. And outputs it to the DDS 132. D
The DS 132 converts the reference clock signal b from the reference clock generation unit 122 into the corrected phase increment set value k × j (k ₀ × j to 16 pixel units) read out in the order of the memory addresses.
k _end × j), f ₀ × j to f _end every 16 pixels
The frequency is sequentially adjusted to the frequency of × j and output to the frequency multiplier 133. The frequency multiplying circuit 133 multiplies the reference clock signal c, which is adjusted in the order of f ₀ × j to f _end × j by the DDS 132 in the order of f ₀ × j to f _end × j, for example, by 4 and outputs the frequency to the synchronization processing unit 134. The synchronization processing unit 134 outputs the reference clock signal d quadrupled by the frequency multiplying circuit 133 as a drawing clock signal f in synchronization with the scanning start signal a from the start sensor 75. Therefore, the drawing clock signal f is scaled down in accordance with the scale down correction rate j. The drawing clock signal f is adjusted by the drawing clock generation circuit 123 in accordance with the set value k of the phase increase, and the raster data is read by the drawing clock signal f which has been scaled down and corrected in accordance with the scaling down correction rate j. The acousto-optic modulator 53 modulates the laser beam based on the drawing signal. The modulated laser beam is applied to the printed wiring board S, and a scaled corrected drawing pattern is formed on the printed wiring board S.

As described above, the main controller 121
Is the polygon mirror 6 calculated by the displacement calculator 89.
7, the phase increase setting value k (k _0-
k _end ) is uniformly corrected in accordance with the scaling correction rate j, and the corrected phase increase set value k × j (k ₀ × j to k) in units of 16 pixels is corrected.
_end × j) is set in the displacement correction memory 131 of the drawing clock generation circuit 123. Drawing clock generation circuit 12
Reference numeral 3 designates a drawing clock signal f of a correction portion in one scan line, which is obtained by correcting the phase increment set value k × j (k ₀ × j to k
The frequency is adjusted to a desired frequency according to _end × j). Therefore, the displacement of the drawing pattern can be corrected, and
This drawing pattern can be scaled down with high accuracy in accordance with the dimensional variation of the printed wiring board S.

When detecting the dimensional change of the printed wiring board S in the main scanning direction, the dimensional change of the printed wiring board S in the sub-scanning direction is also detected. As shown in FIG. 12, for example, of the four positioning holes A at the four corners of the printed wiring board S, two positioning holes A arranged in the sub-scanning direction closer to the CCD camera origin are connected to the CCD cameras 33a and 33a.
Read at 39a. Alignment data calculation unit 111
Calculates the distance Y1 between the two alignment holes A in the sub-scanning direction based on the video signals from the CCD cameras 33a and 39a. The alignment data calculation unit 111
Based on the obtained distance Y1 and the distance in the sub-scanning direction of the positioning hole A given in advance as a dimension reference,
The reduction correction data in the sub-scanning direction is obtained and output to the main controller 121. The main controller 121 realizes the magnification correction in the sub-scanning direction by adjusting the moving speed of the drawing stage 5 by varying the driving pulse to the servo motor 7 in accordance with the magnification correction data in the sub-scanning direction. are doing.

The alignment scope unit 31
, The amount of expansion and contraction of the printed wiring board S is detected, and the alignment data calculation unit 111 calculates magnification reduction data corresponding to the dimensional change of the printed wiring board S based on the amount of expansion and contraction. The scaling correction data according to the dimensional fluctuation can be automatically calculated.

The present invention can be modified as follows.

(1) The drawing reference position sensor 95 only needs to be able to detect the displacement of the laser beam in the main and sub-scanning directions, and is a two-dimensional PSD (Position Detector: Positi
on Sensitive Device), and a plurality of split sensors equivalent to the start sensor 75 may be used.

(2) As a position correcting means for moving the laser beam in the sub-scanning direction, a cylindrical lens 73 is used.
May be adjusted instead of moving the angle of incidence of the laser beam incident on the polygon mirror 67 in the sub-scanning direction. The incident angle of the laser beam in the sub-scanning direction is
A mirror or a lens system provided in a stage preceding the polygon mirror 67 can be changed by driving with an actuator.

(3) In the above embodiment, the laser light source 41 and the acousto-optic modulator 53 are used, but a laser diode may be used instead. In this case, the on / off control of the laser diode may be directly performed, and the structure can be simplified.

(4) In the above embodiment, the imaging optical system 2
1 was fixed and the drawing stage 5 was moved,
Conversely, the present invention is applicable to a configuration in which the imaging optical system 21 moves.

(5) In the above embodiment, the DDS 132 is used for the drawing clock generation circuit 123.
Instead of DS132, voltage controlled oscillator (VCO) or PL
The present invention is applicable even when L (phase locked loop) or the like is used.

(6) In the above-described embodiment, the phase increment set value k in the unit of 16 pixels stored in the misalignment correction memory 131 is read out in the order of addresses in units of 16 pixels, and D
Although it is set in the DS 132, only when the phase increment set value k to the DDS 132 is changed, the corresponding phase increment set value k in 16 pixel units is read from the displacement correction memory 131 and set in the DDS 132. Good. Further, although the phase increment set value k is set in units of 16 pixels, the present invention is not limited to the unit of 16 pixels.
It may be handled as a unit other than 16 pixels.

(7) In the above-described embodiment, the alignment data calculation unit 111 determines the dimensional variation from the actual measurement data of the processing target to obtain the reduction correction data. The double correction data may be supplied to the main controller 121.

(8) In the above embodiment, a printed wiring board manufacturing apparatus has been described as an example. However, the present invention is not limited to such an apparatus, and an apparatus for performing an exposure process using a laser beam. Applicable to

(9) In the above-described embodiment, the means for detecting the drawing position shift (the reference scale 88, the CCD camera, the position shift calculating unit 89, etc.) is always mounted on the laser writing apparatus. The present invention is not limited to this, and may be mounted only when adjusting the drawing clock. Alternatively, the drawing clock may be adjusted using the above-described means while only the imaging optical system 21 excluding the stage 5 is set on an appropriate base. May be.

[0106]

As is apparent from the above description, according to the first aspect of the present invention, among the drawing clocks for one scanning line, the drawing clock of the correction portion is determined according to the positional deviation correction data. Since the signal adjusting means for adjusting the frequency is provided, it is possible to adjust the drawing pitch by the laser beam to be constant without using a plurality of types of clocks whose phases are shifted as in the conventional example. The configuration for generating the clock can be dispensed with, and the displacement of the drawing pattern due to the distortion of the scanning optical system can be corrected with high accuracy with a simple configuration.

According to the second aspect of the present invention, the signal adjusting means includes a memory unit for holding the frequency setting value of the clock at the correction position among the clocks for one scanning line as positional deviation correction data. A direct digital synthesizer that generates a clock having a frequency corresponding to the frequency set value from the memory unit, and a multiplying unit that multiplies the clock from the direct digital synthesizer and outputs the multiplied clock as a drawing clock. Can set the frequency of the drawing clock, can correct the displacement of the drawing pattern in minute units of one pixel or less of raster data, and can accurately correct the displacement of the drawing pattern due to the distortion of the scanning optical system. Can be realized.

Further, according to the third aspect of the present invention, since the signal adjusting means is provided for each of a plurality of laser beams for simultaneous scanning and drawing, multi-beam drawing using a plurality of laser beams is also possible. The displacement of the drawing pattern due to each laser beam can be corrected with high accuracy.

Further, according to the apparatus described in claim 4, since the storage means for storing the positional deviation correction data for each surface of the polygon mirror is provided, the rotation accuracy of the polygon mirror and the rotation unevenness for each surface are provided. The positional deviation of the drawing pattern due to the distortion of the scanning optical system is corrected with high accuracy for each surface of the polygon mirror.

According to the apparatus described in claim 5, the scanning speed distribution detecting means for detecting the scanning speed distribution of the laser beam for each surface of the polygon mirror, and the scanning speed distribution detecting means detecting the scanning speed distribution. A calculation means for calculating positional deviation correction data for each surface of the polygon mirror so that the drawing pitch of each surface of the polygon mirror by the laser beam is constant. It is possible to accurately correct the positional deviation of the drawing pattern due to the rotation accuracy of the polygon mirror and the uneven rotation of each surface for each surface of the polygon mirror.

According to the apparatus of the present invention, a reference laser beam different from the drawing laser beam is received via the polygon mirror to generate a drawing clock for each surface of the polygon mirror. With the provision of the generating means, it is possible to configure a laser drawing apparatus that cancels out a drawing position shift due to a change in scanning speed for each polygon surface, and it is possible to correct a pitch error in generating a drawing clock by the generating means, Can be corrected, and the positional deviation of the drawing pattern can be corrected with high accuracy.

According to the apparatus described in claim 7, an expansion / contraction amount detecting means for detecting an expansion / contraction amount of an object to be processed,
A calculation unit that corrects the displacement correction data in accordance with the expansion amount detected by the expansion amount detection unit,
The displacement of the drawing pattern due to the distortion of the scanning optical system can be corrected with high accuracy, and the drawing pattern can be scaled down with high accuracy according to the dimensional change of the processing target.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of a printed wiring board manufacturing apparatus which is an example of a laser drawing apparatus according to the present invention.

FIG. 2 is a detailed plan view of the printed wiring board manufacturing apparatus.

FIG. 3 is a detailed side view of the printed wiring board manufacturing apparatus.

FIG. 4 is a side view showing a schematic configuration of a position correction mechanism.

FIG. 5 is a plan view showing a schematic configuration of a position correction mechanism.

FIG. 6 is a front view showing a schematic configuration of a position correction mechanism.

7A is a perspective view illustrating a configuration of a start sensor, and FIG. 7B is a diagram illustrating a detection waveform of the start sensor.

FIG. 8 is a plan view showing a configuration of a drawing reference position sensor.

FIG. 9 is a block diagram illustrating a schematic configuration of a printed wiring board manufacturing apparatus according to an embodiment.

FIG. 10 is a block diagram illustrating a configuration of a main part of a drawing control unit.

FIG. 11 is a block diagram illustrating a configuration of a DDS.

FIG. 12 is a diagram showing a drawing coordinate system in the embodiment device.

13A is a diagram illustrating a multi-beam array and its beam interval, and FIG. 13B is a diagram illustrating a drawing vector.

FIG. 14A is a diagram illustrating a portion where a drawing pattern is misaligned, and FIG. 14B is a diagram in which the misalignment of the drawing pattern illustrated in FIG.

15A is a diagram showing ideal and actual scanning optical characteristics, FIG. 15B is a diagram showing characteristics of a main scanning speed of a laser beam, and FIG. It is a figure which shows a correction characteristic, and (d) is a figure which shows the characteristic of the drawing pitch after adjustment.

FIG. 16 is a diagram showing a displacement correction memory map.

FIG. 17 is a timing chart showing timing for setting a frequency in the DDS.

FIG. 18 is a block diagram showing a schematic configuration in a case where a generator for generating a drawing clock signal from a reference laser beam is provided in the printed wiring board manufacturing apparatus of the embodiment.

FIG. 19A is a diagram showing the scanning distortion characteristics of the laser beams CH1 and CH2, and FIG.
FIG. 9 is a diagram illustrating correction characteristics of the laser beam No. 2;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Base 3 ... Guide rail (moving means) 5 ... Drawing stage (mounting table) 7 ... Servo motor (moving means) 9 ... Feed screw (moving means) 15 ... Mounting table 21 ... Imaging optical system 31 ... Alignment Scope unit (expansion and contraction amount detecting means) 33a CCD camera (scanning speed distribution detecting means) 41 laser light source 53 acousto-optic modulator (modulating means) 67 polygon mirror (deflecting means) 73 cylindrical lens 75 start sensor (Scanning speed distribution detecting means) 81 ... position correcting mechanism 88 ... reference scale (scanning speed distribution detecting means) 89 ... positional deviation calculating unit (calculating means) 95 ... drawing reference position sensor (scanning speed distribution detecting means) 111 ... alignment data calculation Section (expansion / contraction amount detecting means) 121 ... Main controller (computing means) 12 Reference clock generator 123 Drawing clock generation circuit (signal adjustment means) 126 Polygon surface detector (scanning speed distribution detection means) 131 Position shift correction memory 132 DDS (Signal adjustment means) 133 Frequency multiplication circuit (Multiplier) Means) 134: Synchronization processing unit (multiplier means) S: Printed wiring board (object to be processed) LB: Laser beam

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroyuki Shirota 4-chome Tenjin Kitamachi 1-chome, Horikawa-dori-Terauchi, Kamigyo-ku, Kyoto Dai-Nippon Screen Manufacturing Co., Ltd. (72) Inventor Akira Kuwahara Kamigyo, Kyoto-shi 4-chome Tenjin, Horikawa-dori-Tenouchi-ku, 1-chome, Kitamachi 1 Dainippon Screen Manufacturing Co., Ltd. F term (reference) 2C362 BA56 BA68 BB23 BB28 BB39 BB40 CB47 CB78 2H045 AA01 BA02 BA34 CA63 CA72 CA83 CA88 CA97 5C072 AA03 CA06 DA02 HA02 HA06 HA13 HA16 HB06 HB08 HB13 NA01 XA05 5C074 BB03 CC22 CC26 DD15 DD24 EE02 EE06

Claims (7)

[Claims] 1. A laser beam is modulated on the basis of a drawing signal generated by raster data read by a drawing clock of a predetermined frequency, and the modulated laser beam is deflected in a main scanning direction by a deflecting means. A laser writing apparatus for writing a desired pattern on the processing target by irradiating the processing target with a laser beam and a mounting table relatively in a sub-scanning direction by a moving unit; And a signal adjusting unit that adjusts a drawing clock of a correction portion among the drawing clocks to a frequency corresponding to the positional deviation correction data. 2. The laser writing apparatus according to claim 1, wherein the signal adjusting unit includes: a memory unit that holds a frequency setting value of a clock at a correction position among clocks of one scanning line as positional deviation correction data. A direct digital synthesizer that generates a clock having a frequency according to a frequency set value from the memory unit; Laser drawing device. 3. The laser writing apparatus according to claim 1, wherein said signal adjusting means is provided for each of a plurality of laser beams for simultaneous scanning and writing. 4. The laser writing apparatus according to claim 1, wherein said deflecting means is a scanning system including a polygon mirror, and stores positional deviation correction data for each surface of said polygon mirror. A laser writing apparatus comprising storage means. 5. The laser writing apparatus according to claim 4, wherein the scanning speed distribution detecting means detects a scanning speed distribution of a laser beam for each surface of the polygon mirror, and the scanning speed distribution detecting means detects the scanning speed distribution. A laser writing apparatus, comprising: calculating means for calculating displacement correction data for each surface of the polygon mirror so that the drawing pitch of each surface of the polygon mirror by the laser beam is constant. 6. The laser writing apparatus according to claim 1, wherein the deflecting unit is a scanning system including a polygon mirror, and a reference laser beam different from the drawing laser beam is used as the polygon. A laser writing apparatus, comprising: generating means for receiving a light via a mirror and generating a writing clock for each surface of a polygon mirror. 7. The laser writing apparatus according to claim 1, wherein an amount of expansion and contraction of the object to be processed is detected, and an amount of expansion and contraction detected by the amount of expansion and contraction of the object is detected. And a calculating means for correcting the positional deviation correction data in accordance with (1).