JPH11109273A - Laser plotting device having light quantity detecting/ adjusting function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser plotting device measuring a light quantity of a laser beam in a dynamic state and adjusting the light quantity of the laser beam. SOLUTION: The laser plotting device scans a body to be plotted 28 by the laser beam LB to plot/record a prescribed pattern based on the raster data on it. Laser beam modulation-cum-light quantity adjustment means 12, 14 modulate the laser beam for plotting/recording the prescribed pattern according to the raster data, and adjust the light quantity of the laser beam, and light quantity measurement means 34, 36 measure the light quantity of the laser beam in the dynamic state of the laser beam. An operation means compares the light quantity numerical value data obtained from the light quantity measurement means with the prescribed specified numerical value data, and operates the difference data, and controls the light quantity of the laser beam so that the difference data become within the allowable range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser writing apparatus which scans a drawing object with a laser beam and writes and records a predetermined pattern based on raster data on the drawing object.

[0002]

2. Description of the Related Art A laser drawing apparatus as described above is used for drawing and recording a circuit pattern when a printed circuit board is manufactured by using, for example, a photolithographic technique, and a drawing object, for example, a photosensitive film for a photomask or a substrate. By modulating the laser beam according to the drawing raster data while scanning the photoresist layer with the laser beam, a desired circuit pattern is recorded on the object to be drawn. In such a laser drawing apparatus, the light intensity of the laser beam must be adjusted in accordance with changes in process conditions, such as the properties of a developer or a photosensitive material after drawing. Becomes indispensable.

[0003]

The light quantity measuring device used in the conventional laser drawing apparatus measures the light quantity of the laser beam when the laser beam is stationary with respect to the light quantity measuring optical sensor. That is what you are going to do. Therefore, conventionally, when adjusting the light amount of the laser beam on the focal plane when the laser beam drawing apparatus is in operation, the scanning operation of the laser beam is temporarily stopped and the light amount of the laser beam is measured. Must do. Needless to say, stopping the scanning operation of the laser beam every time the light amount of the laser beam is adjusted is a troublesome operation.

Accordingly, it is an object of the present invention to provide a laser writing apparatus which is capable of measuring the light amount of a laser beam in a dynamic state and capable of adjusting the light amount of the laser beam.

[0005]

According to a first aspect of the present invention, there is provided a laser drawing apparatus which scans a drawing object with a laser beam and draws and records a predetermined pattern based on raster data on the drawing object. Means for modulating a laser beam in accordance with raster data for writing and recording of a predetermined pattern and adjusting a light amount of the laser beam; and measuring a light amount of the laser beam under a dynamic state of the laser beam. A light quantity measuring means for calculating the light quantity numerical data obtained from the light quantity measuring means with predetermined specified numerical data to calculate the difference data; and the difference data obtained by the calculating means is within an allowable range. Control means for controlling the light amount adjustment by the laser beam modulation and light amount adjustment means.

In the first aspect of the present invention, preferably, the laser beam modulating means and the light amount adjusting means include an acousto-optic device for injecting a laser beam, and a high-frequency drive signal applied to the acousto-optic device in accordance with raster data. And an acousto-optic element driving means for outputting the laser beam and modulating the laser beam, wherein the control means adjusts the amplitude of the high-frequency driving signal from the acousto-optic element driving means to the acousto-optic element according to the difference data. It has become.

A laser drawing apparatus according to a second aspect of the present invention scans a drawing object with a laser beam and draws and records a predetermined pattern based on raster data on the drawing object. A laser beam modulating means for modulating a laser beam according to raster data, a light amount adjusting means for adjusting a light amount of the laser beam from the laser beam modulating means, and a light amount of the laser beam under a dynamic state of the laser beam. Light quantity measuring means for measuring, light quantity numerical data obtained from the light quantity measuring means, and calculating means for calculating difference data by comparing the numerical data with predetermined designated numerical data, and the difference data obtained by this calculating means is within an allowable range. Control means for controlling the light quantity adjustment by the light quantity adjustment means so as to be inside.

In a second aspect of the present invention, preferably, the light amount adjusting means includes a variable light amount adjusting filter,
Variable filter driving means for driving the variable light amount adjusting filter, and the control means controls the variable filter driving means in accordance with the difference data.

In the present invention, the above-mentioned light quantity measuring means includes a light detecting means for detecting a laser beam under its dynamic state,
Detection signal output means for outputting a detection signal when the laser beam is detected by the light detection means; output signal holding means for temporarily holding the output signal from the light detection means when the laser beam is detected by the light detection means; Detection data capturing means for capturing the holding signal as detection data from the output signal holding means in response to the output of the detection signal from the output means, and conversion means for converting the detection data captured by the detection data capturing means into light intensity numerical data May be provided.

The above-mentioned light quantity measuring means includes a light detecting means for detecting a laser beam in a dynamic state, a detection signal outputting means for outputting a detection signal when the light detecting means detects a laser beam, and a light detecting means. Output signal holding means for temporarily holding an output signal from the light detection means at the time of detecting a laser beam, and the held signal from the output value holding means as detection data in response to the output of the detection signal from the detection signal output means. And a detection data capturing means for capturing the detection data. At this time, the detection data capturing means captures the detection data from the output value holding means every time the detection signal is output from the detection signal output means. In this case, the light quantity measuring means further calculates average value data of the plurality of pieces of detection data taken in by the detection data taking means, and converts the average value data obtained by the mean value calculation means into light quantity numerical data. Conversion means for converting the

In the present invention, preferably, the output value holding means includes a peak hold circuit for holding a peak value of an output value from the light detection means, and an analog / digital conversion for converting an output value of the peak hold circuit into a digital value. And detection data means taking-in means taking in an output value from the analog / digital converter as detection data. In this case, the detection signal output means may comprise a trigger circuit for outputting a trigger signal as a detection signal when detecting the laser beam by the light detection means.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a laser writing apparatus according to the present invention will be described with reference to the accompanying drawings.

Referring to FIG. 1, there is shown a schematic block diagram of a system centering on a laser writing apparatus according to the present invention. As is apparent from the figure, the laser writing apparatus includes a laser oscillator 10, 10 generates, for example, an argon laser, and emits the argon laser to the acousto-optic device (AOM) 12 as a laser beam LB.

Referring to FIG. 2, a schematic configuration of the AOM 12 is shown, which includes a suitable transparent dielectric 12A,
And a piezoelectric element 12B attached to the dielectric 12A. When a high-frequency drive voltage is applied from the AOM control circuit 14 to the piezoelectric element 12B, the piezoelectric element 12B
High-frequency vibration is generated in 2A, and a diffraction grating based on a density difference is formed there. Therefore, when the high frequency drive signal is not applied to the piezoelectric element 12B, the laser beam LB incident on the dielectric 12A goes straight and proceeds toward the light shielding plate 12C, so that the laser beam LB is not emitted from the AOM 12. Absent. On the other hand, when a high-frequency drive voltage is applied to the piezoelectric element 12B, the above-described diffraction grating is formed on the dielectric 12A, so that the laser beam LB is diffracted and deviates from the light shielding plate 12C and is emitted from the AOM 12. .

During the drawing operation, raster data is sequentially output from the drawing data processing circuit 16 to the AOM control circuit 14,
The AOM control circuit 14 outputs a high-frequency drive signal according to the raster data. That is, the raster data has data "1" as a binarized data for a color-developed pixel, and has data "0" for a non-color-developed pixel. When the color pixel data is “1”, the AOM control circuit 1
4 outputs a high-frequency drive signal to the AOM 12. In short, the laser beam LB incident on the AOM 12
Is modulated according to raster data output from the drawing data processing circuit 16.

As is well known, the AOM control circuit 14
The diffraction direction of the laser beam LB is changed by adjusting the frequency of the high-frequency drive signal output from the AOM 12 to the AOM 12, and the intensity, that is, the light amount of the laser beam LB is changed by adjusting the amplitude of the high-frequency drive signal. Can be.

In the present embodiment, the laser drawing apparatus has an LA
An N interface circuit 18 is provided, and the LAN interface circuit 18 is connected to a LAN (local area network).
Through a network) to a suitable controller, such as an engineering workstation (EWS) 20. The EWS 20 holds various vector data as drawing data to be drawn and recorded by the laser drawing apparatus, and when drawing is performed, the vector data is appropriately transferred to the laser drawing apparatus. The transferred vector data is once taken into the LAN interface circuit 18.

The vector data taken in by the LAN interface circuit 18 is sequentially sent to the drawing data processing circuit 16, where it is converted into raster data and output to the AOM control circuit 14, which outputs the data as described above. A high frequency drive signal is output to the AOM 12 based on the raster data.

The operations of the AOM control circuit 14, the drawing data processing circuit 16 and the LAN interface circuit 18 are controlled by a control circuit 22.
Reference numeral 2 denotes a microcomputer. That is, the control circuit 22 includes a central processing unit (CPU) 22A and a read-only memory (ROM) 22 for storing programs for executing various routines, conversion tables, constants, and the like.
B, a writable / readable memory (RAM) 22C for temporarily storing data and the like, and an input / output interface (I / O) circuit 22D.

As schematically shown in FIG. 1, the laser drawing apparatus includes a polygon mirror 24, and a laser beam LB emitted from the AOM 12 is made incident on a rotating reflection surface of the polygon mirror 24. The laser beam LB incident on each reflection surface of the polygon mirror 24 is deflected in the main scanning direction (FIG. 1) with respect to the drawing table 26. On the other hand, the drawing table 26 is moved in a direction perpendicular to the main scanning direction, that is, in the sub-scanning direction, in units of one pixel pitch of raster data.

In other words, by moving the drawing table 26 to the sub-scan while scanning the drawing object 28 mounted on the drawing table 26 with the laser beam LB, the drawing object 26 is based on the raster data. A predetermined pattern is drawn and recorded.

As shown in FIG. 1, an fθ lens 30 is interposed between the polygon mirror 24 and the drawing table 26. The fθ lens 30 allows the laser beam to focus on a line segment along the main scanning direction. Will always be focused on.

A detection mirror 32 is provided above the drawing table 26, and the detection mirror 32 is appropriately supported by a frame (not shown) of the laser drawing apparatus.
The detection mirror 32 is arranged at one end of the main scanning range of the laser beam LB, and is made incident on the detection mirror 32 when the laser beam LB reaches the end of the main scanning range. When the laser beam LB is incident on the detection mirror 32,
The incident laser beam LB is reflected toward the photodetector 34, and the photodetector 34 converts the laser beam LB into a voltage signal corresponding to the intensity, that is, the light amount. Photodetector 34
Outputs the electric signal to the light amount detection circuit 36, where the light amount of the laser beam LB is detected, and the detected light amount data is transmitted to the control circuit 22 via the I / O circuit 22D.
In the RAM 22C.

More specifically, in this embodiment, a photodiode (P / D) is used as the photodetector 34, a predetermined voltage is applied to the cathode side of the photodiode 34, and a load is applied to the anode side. A resistor or the like is connected. When the laser beam LB is incident on the photodiode 34, a voltage signal corresponding to the amount of light is generated.
Is output from the anode side of.

Referring to FIG. 3, there is shown a detailed block diagram of the light quantity detection circuit 36. As is apparent from FIG. 3, the light quantity detection circuit 36 includes an amplifier (AMP) 36A and a peak hold circuit (P / H) 36B. , Analog / digital (A /
D) A converter 36C is provided. The voltage signal output from the photodiode 34 is first amplified by an amplifier 36A, and the peak value of the amplified voltage signal is applied to a P / H circuit 36B.
Is held by Next, the peak value held by the P / H circuit 36B is output to the A / D converter 36C. In short, the P / H circuit 36B and the A / D converter 36
C functions as output value holding means for temporarily holding the output value from the photodetector 34.

The light amount detection circuit 36 further includes a trigger circuit 36
D, and the photodetector 34 amplified by the amplifier 36A.
Are also output to the trigger circuit 36D. A comparator is built in the trigger cycle 36D, and a voltage value of about 1/10 of the measurement range is set as a threshold value in this comparator. When the output voltage value from the amplifier 36A exceeds the threshold value, a trigger signal is output from the trigger circuit 36D as a light detection signal to the I / O circuit 22 of the control circuit 22.
D is output.

The trigger signal from the trigger circuit 36D is I / O
When output to the circuit 22D, the control circuit 22 forms a sampling signal based on the trigger signal, and the sampling signal is output to the A / D converter 36C. The output of the sampling signal to the A / D converter 36C is delayed by a predetermined time from the reception of the trigger signal, and the detection peak value of the P / H circuit 36B becomes stable as the time elapses.

When the sampling signal is output to the A / D converter 36C, the P / H circuit 36B outputs the signal to the A / D converter 36C.
C, the peak value of the detected voltage output (ie, P /
The value held by the H circuit 36B) is taken into the control circuit 22 as light detection data, and is temporarily stored in the RAM 22C. Next, the control circuit 22 converts the light detection data into light amount data based on a conversion table or conversion formula stored in the ROM 22B in advance, and the light amount data is also temporarily stored in the RAM 22C.

Further, the control circuit 22 sends an I / O circuit 22D
, A discharge command voltage signal is output to the P / H circuit 36B, and this discharge command voltage signal is normally maintained at a low level. At this time, the peak value of the detected voltage is detected by the P / H circuit 36B. Is maintained. However, when the discharge command voltage signal is switched from the low level to the high level, the retained charge (that is, the peak voltage value) is discharged from the P / H circuit 36B, and the output of the P / H circuit 36B is dropped to the ground level. It is. P / H circuit 36B
, The discharge command voltage signal is returned from the high level to the low level again.

Referring to FIG. 4, the AOM control circuit 14 is shown in detail, and as shown in FIG.
Is provided with a drive circuit 14A that generates a high-frequency drive signal to be output to the AOM 12. The drive circuit 14A receives raster data from the drawing data processing circuit 16 on the one hand, and digital / analog (D /
A) The amplitude data is received from the control circuit 22 via the converter 14B and the buffer amplifier 14C. The output of the high-frequency drive signal from the drive circuit 14A to the AOM 12 is performed when the raster data is “1”, and the amplitude of the high-frequency drive signal is determined according to the amplitude data output from the control circuit 22.

The above-mentioned amplitude data is created from light detection data obtained from the light amount detection circuit 36, that is, light amount data obtained by converting the detected data based on a conversion table or a conversion formula. That is, by adjusting the amplitude data based on the light amount data from the light amount detection circuit 36, the AOM 12
Of the laser beam LB emitted from the target can be set to the target value.

More specifically, the amplitude data of the high-frequency drive signal output from the drive circuit 14A is set to V. At this time, AO
Assuming that the light amount data of the laser beam LB emitted from M12 is p, the following relationship may be established between the amplitude data V and the light amount data p. V = f (p)

[0033] Here, the measurement light quantity data p 'and, also when the target light quantity data and the p _0, measured light intensity data p'
And amplitude data V 'and V ₀ corresponding respectively to the target light quantity data p ₀ can be expressed as follows. V ′ = f (p ′) V ₀ = f (p ₀ )

Next, the difference ΔV between the amplitude data V ′ and V ₀ is obtained by the following calculation. ΔV = V ₀ −V ′ By adding this difference ΔV to the amplitude data V ′ at the time of light quantity measurement, the amplitude data V to be output to the drive circuit 14A is obtained.
Is created, whereby the light amount of the laser beam LB can be approximated to the target light amount (p ₀ ).

FIG. 5 is a flowchart of a light amount correction routine executed by the laser drawing apparatus shown in FIG.
The light amount correction will be described below with reference to this. The light amount correction routine is executed immediately before the start of the drawing operation in the laser drawing device.

In step 501, a light quantity measurement routine is executed, whereby measured light quantity data p 'of the laser beam LB is obtained. The light amount measurement routine will be described later with reference to the flowchart shown in FIG.

In step 502, the following calculation is performed.
Difference data Δp between the target light amount data p ₀ and the measured light amount data p ′ is obtained. Δp ← p ₀ −p ′ Note that the target light amount data p ₀ is created by the EWS 20 based on a change in the process condition of the object to be drawn, and is transferred from the EWS 20 to the control circuit 22 in advance and held in the RAM 22C. It is.

At step 503, it is determined whether or not the difference data Δp is within the allowable range −a ≦ Δp ≦ + a.
If | Δp |> a, the process proceeds to step 504, where the following calculation is performed. V ′ ← f (p ′) V ₀ ← f (p ₀ ) Subsequently, in step 505, the following calculation is performed. ΔV ← V ₀ −V ′

Further, at step 506, the following calculation is performed: V ← V '+ ΔV The calculation result V is output from the control circuit 22 to the control circuit 22 as amplitude data.
The amplitude data V is output to the D / A converter 14B of the OM control circuit 14, where the amplitude data V is converted from a digital signal to an analog signal, and is then amplified by the buffer amplifier 14C and then input to the drive circuit 14A. Thus, AOM
The amplitude value of the high-frequency drive signal output from the control circuit 14 to the AOM 12 is changed according to the difference data Δp, and the light amount of the laser beam LB is approximated to the target value (p ₀ ).

Thereafter, the flow returns to step 501, and the same routine is repeated until the difference data Δp is included in the allowable range −a ≦ Δp ≦ + a, that is, until | Δp | ≦ a in step 503.

When | Δp | ≦ a at step 503,
The light amount correction routine ends. Thus, the light amount of the laser beam LB is made to coincide with the target value within the allowable range, so that an appropriate drawing / recording operation using the laser beam LB can be performed.

Next, the light quantity measurement routine will be described with reference to the flowchart shown in FIG. FIG. 7 shows a timing chart of various parameters associated with the execution of the light amount measurement routine.

At step 601, the counter n is reset. Next, at step 602, the trigger circuit 36
It is determined whether or not a trigger signal has been output from D. When the laser beam LB is repeatedly deflected by the reflection surface of the polygon mirror 24, the laser beam detection by the photodetector 34 is as shown in the timing chart of FIG. That is, laser beam detection is performed by the photodetector 34 at predetermined time intervals, and a voltage signal proportional to the detected light amount is detected from the photodetector 34 every time the laser beam is detected.

As described above, such a detected voltage signal is amplified by the amplifier 26A and then sample-hold (P / P).
H) Output to the circuit 26B and the trigger circuit 36D. As described above, when the peak value of the detection voltage signal is held by the P / H circuit 36B, the peak value becomes P / H
The signal is output from the circuit 36B to the A / D converter 36C (FIG. 3). On the other hand, the detection voltage signal output from the amplifier 36A is also output to the trigger circuit 36B, and when the voltage level of the detection voltage signal exceeds a predetermined threshold value, the trigger circuit 3
The trigger signal is sent from the 6D to the I / O circuit 22D of the control circuit 22.
(FIG. 7).

In step 602, the trigger circuit 36
When the output of the trigger signal from D is confirmed, step 6
03, where sampling from the A / D converter 36C is performed with a delay of a predetermined time from the output of the trigger signal (FIG. 7). That is, the control circuit 22 determines the peak value of the detection voltage output from the P / H circuit 36B to the A / D converter 36C (that is, the held value held by the P / H circuit 36B).
The taking as light detection data SD _n. Then, the process proceeds to step 604, where the light detection data SD _n is RAM2
It is temporarily stored in 2C.

[0046] When the storage of the light detection data SD _n to RAM22C is completed, the process proceeds to step 605, where P / H
The charge (peak value) of the circuit 36B is discharged, and its output is set to the ground level. Next, at step 606, it is determined whether or not the count number of the counter n is equal to "4". When n ≠ 4, the process proceeds from step 606 to step 607, where the count of the counter n is incremented by “1”, and then returns to step 602. Thereafter, the routine consisting of steps 602 to 607 is repeated until the count number of the counter n reaches “4”.

At step 606, when the count number of the counter n reaches "4", that is, five times of light detection is performed by the photodetector 34, and each light detection is performed by the A / D converter 36C. when sampling is performed five times, the process proceeds from step 606 to step 608, where in order to not photodetecting data SD ₀ the average value SD of the SD ₄ (n = 0,1,2,3,4), as follows Operation is performed. SD ← ΣSD _n / 5

In short, in this embodiment, light detection is performed five times, and the influence of measurement errors is reduced by obtaining the average value of the five light detection data. In this embodiment, the light detection is repeated five times, but of course, the number of repetitions is arbitrary.

In step 609, the average value SD is converted into light quantity measurement data p 'based on a conversion table or conversion formula stored in the ROM 22B of the control circuit 22 in advance. Next, at step 610, the light quantity measurement data p 'is temporarily stored in the RAM 22C. Thereafter, the flow returns to step 502 of the light quantity correction routine shown in FIG. The above conversion table or conversion formula is created based on calibration data obtained from the relationship between known light amount data and detection characteristics of the photodetector 34.

Referring to FIG. 8, there is shown a second preferred embodiment of the laser writing apparatus according to the present invention, in which the same reference numerals are used for the same components as those shown in FIG. In the second embodiment, the AOM control circuit 1
4, the amplitude value of the high-frequency drive signal output to the AOM 12 is maximized. Therefore, the light intensity, that is, the light amount of the laser beam LB emitted from the AOM 12 is always maximized, and the light amount adjustment of the laser beam LB is performed by the AOM 12 Is performed by an optical variable filter 38 provided for the emission laser beam LB. Except for this point, the other configuration is substantially the same as the first embodiment shown in FIG.

More specifically, the optically variable filter 38 is formed as, for example, a rotary filter capable of continuously changing the light transmission amount of the laser beam LB. That is, the light transmittance of the rotary filter 38 changes continuously along the circumferential direction. By rotating the rotary filter, the light transmission amount of the laser beam LB is continuously adjusted. Such a rotary filter 38 is rotated in a forward direction or a reverse direction by, for example, a stepping motor or a servomotor. In the second embodiment, when the rotary filter 38 is rotated in the normal direction, the amount of light transmission increases, and when the rotary filter 38 is rotated in the reverse direction, It is assumed that the light transmission amount decreases. The motor itself is driven by a drive pulse output from the variable filter drive circuit 40 to the motor, and the control circuit 22 controls the output of the drive pulse.

As described above, by maximizing the amplitude value of the high frequency drive signal output from the AOM control circuit 14 to the AOM 12, the light intensity, that is, the light amount of the laser beam LB emitted from the AOM 12 is maximized. So
By rotating the rotary filter and stopping at a predetermined rotation position, the laser beam LB having a desired light amount
Is obtained.

Referring to FIG. 9, there is shown a flowchart of a light amount correction routine in the second embodiment of the laser writing apparatus according to the present invention. The light amount correction routine is executed immediately before the start of the drawing operation in the laser drawing device.

In step 901, the light quantity measurement routine shown in FIG. 6 is executed, whereby the measured light quantity data p 'of the laser beam LB is obtained.

In step 902, the following calculation is performed.
Difference data Δp between the target light amount data p ₀ and the measured light amount data p ′ is obtained. Δp ← p ₀ −p ′ Note that, similarly to the first embodiment, the target light amount data p
₀ is EWS based on the change of the process condition of the object to be drawn, etc.
20 and the control circuit 22 from the EWS 20 in advance.
And stored in the RAM 22C.

In step 903, it is determined whether or not the difference data Δp is within the allowable range −a ≦ Δp ≦ + a.
If | Δp |> a, the process proceeds to step 904, where it is determined whether Δp is positive or negative.

[0057] If a Delta] p ≧ 0, that is, if the measurement light quantity data p 'is smaller than the target light quantity data p _0, the flow proceeds to step 905, where | Delta] p | number of drive pulses corresponding is converted to its conversion driving The variable filter, that is, the rotary filter 38 is rotated in the forward direction by the number of pulses, whereby the light amount of the laser beam LB is approximated to the target value (p ₀ ).

On the other hand, in step 904, Δp <0
, Ie, the measured light amount data p ′ is the target light amount data p
If greater than ₀ , proceed to step 906, where | Δ
The number of driving pulses corresponding to p | is converted, and the variable filter, that is, the rotary filter 38 is rotated in the reverse direction by the converted number of driving pulses, whereby the light amount of the laser beam LB is approximated to the target value (p ₀ ). Will be.

Thereafter, the flow returns to step 901 to repeat the same routine until the difference data Δp is included in the allowable range −a ≦ Δp ≦ + a, that is, until | Δp | ≦ a in step 903.

When | Δp | ≦ a is satisfied in step 903,
The light amount correction routine ends. Thus, the light amount of the laser beam LB is made to coincide with the target value within the allowable range, and a proper drawing / recording operation by the laser beam LB can be performed.

In the above-described embodiment, the light quantity correction routine is performed immediately before the execution of the drawing recording by the laser drawing apparatus. However, it can be performed during the drawing recording by the laser drawing apparatus. For example, in a case where the drawing recording is performed under the same process condition and then the drawing recording is performed under another process condition, the difference data ΔD is obtained in advance during the former drawing recording, and based on the difference data ΔD. The correction data may be prepared in advance so that the former drawing recording is completed and the latter drawing recording can be performed immediately.

[0062]

As is apparent from the above description, in the laser writing apparatus according to the present invention, the amount of light can be accurately adjusted without stopping the scanning operation of the laser beam. It can contribute to efficiency.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of a laser writing apparatus according to the present invention.

FIG. 2 is a schematic diagram showing a schematic configuration of the acousto-optic device of FIG.

FIG. 3 is a detailed block diagram of a light amount detection circuit of FIG. 1;

FIG. 4 is a detailed block diagram of the AOM control circuit of FIG. 1;

FIG. 5 is a flowchart showing a light amount correction routine executed by the laser drawing apparatus of FIG. 1;

FIG. 6 is a flowchart showing a light amount measurement routine executed as a subroutine in the light amount correction routine of FIG. 5;

FIG. 7 is a timing chart when the light quantity measurement routine of FIG. 6 is executed.

FIG. 8 is a block diagram showing a second embodiment of the laser writing apparatus according to the present invention.

FIG. 9 is a flowchart illustrating a light amount correction routine executed by the laser drawing apparatus of FIG. 8;

[Explanation of symbols]

Reference Signs List 10 laser oscillator 12 acousto-optic element (AOM) 14 AOM control circuit 16 drawing data processing circuit 18 LAN interface circuit 20 engineering workstation (EW
S) 22 control circuit 24 polygon mirror 26 drawing table 28 object to be drawn 30 fθ lens 32 detection mirror 34 photodetector 36 light quantity detection circuit 38 optical variable filter 40 variable filter drive circuit

Claims (12)

[Claims] 1. A laser writing apparatus which scans an object to be drawn with a laser beam and draws and records a predetermined pattern based on raster data on the object to be drawn, wherein the laser beam is used for drawing and writing the predetermined pattern. Laser beam modulation and light amount adjusting means for modulating the light amount of the laser beam while modulating according to the raster data; light amount measuring means for measuring the light amount of the laser beam in a dynamic state of the laser beam; Calculating means for calculating the difference data by comparing the numerical data of the light quantity obtained from the predetermined numerical data with the specified numerical data; and the laser beam modulation and light quantity so that the difference data obtained by the calculating means falls within an allowable range. A laser writing apparatus comprising: a control unit that controls light amount adjustment by the adjustment unit. 2. A laser drawing apparatus according to claim 1, wherein said laser beam modulation means and light quantity adjustment means apply an acousto-optic element for injecting said laser beam, and apply a high-frequency drive signal to said acousto-optic element in accordance with said raster data. Acousto-optic element driving means for outputting and modulating the laser beam, wherein the control means adjusts the amplitude of a high-frequency driving signal from the acousto-optic element driving means to the acousto-optic element according to the difference data. A laser writing apparatus. 3. The laser writing apparatus according to claim 1, wherein said light quantity measuring means detects said laser beam in a dynamic state, and said light detecting means detects said laser beam when detecting said laser beam. Detection signal output means for outputting a signal; output signal holding means for temporarily holding an output signal from the light detection means at the time of laser beam detection by the light detection means; output of a detection signal from the detection signal output means And a conversion means for converting the detection data fetched by the detection data fetching means into light intensity numerical data. Laser drawing apparatus. 4. The laser writing apparatus according to claim 1, wherein said light quantity measuring means detects said laser beam in a dynamic state thereof, and said light quantity detecting means detects said laser beam when detecting said laser beam. Detection signal output means for outputting a signal; output signal holding means for temporarily holding an output signal from the light detection means at the time of laser beam detection by the light detection means; output of a detection signal from the detection signal output means Detection data capturing means for capturing the holding signal from the output value holding means as detection data according to the detection data capturing means, wherein the detection data capturing means holds the output value every time a detection signal is output from the detection signal output means. Means for taking in detection data from the means, and furthermore, an average value of a plurality of pieces of detection data taken in by the means for taking in detection data. An average value calculating means for calculating a chromatography data, laser drawing apparatus characterized by comprising a conversion means for converting the average value data obtained by said average value calculating means to the light quantity numerical data. 5. A laser writing apparatus according to claim 3, wherein said output value holding means holds a peak value of an output value from said light detection means,
An analog / digital converter for converting an output value of the peak hold circuit into a digital value, wherein the detection data acquisition means acquires an output value from the analog / digital converter as detection data. Laser drawing equipment. 6. A laser beam drawing apparatus according to claim 5, wherein said detection signal output means comprises a trigger circuit for outputting a trigger signal as a detection signal when the light detection means detects a laser beam. apparatus. 7. A laser writing apparatus which scans an object to be drawn with a laser beam and draws and records a predetermined pattern based on raster data on the object to be drawn, wherein the laser beam is used for drawing and recording the predetermined pattern. Laser beam modulating means for modulating according to the raster data; light quantity adjusting means for adjusting the light quantity of the laser beam from the laser beam modulating means; light quantity measurement for measuring the light quantity of the laser beam in a dynamic state of the laser beam Means, light amount numerical data obtained from the light amount measuring means, and arithmetic means for calculating difference data by comparing the numerical value data with predetermined designated numerical data, and the difference data obtained by the arithmetic means is within an allowable range. And a control means for controlling light amount adjustment by the light amount adjusting means. 8. A laser writing apparatus according to claim 7, wherein said light amount adjusting means includes a variable light amount adjusting filter, and a variable filter driving means for driving said variable light amount adjusting filter. A laser writing apparatus, wherein the variable filter driving means is controlled according to the difference data. 9. The laser writing apparatus according to claim 7, wherein said light quantity measuring means detects said laser beam in a dynamic state, and said light detecting means detects said laser beam when detecting said laser beam. Detection signal output means for outputting a signal; output signal holding means for temporarily holding an output signal from the light detection means at the time of laser beam detection by the light detection means; output of a detection signal from the detection signal output means Detection data capturing means for capturing the holding signal from the output signal holding means as detection data in response to the detection signal, and conversion means for converting the detection data captured by the detection data capturing means into light intensity numerical data. Laser drawing apparatus. 10. The laser writing apparatus according to claim 7, wherein said light quantity measuring means detects said laser beam in a dynamic state, and said light detecting means detects said laser beam when said laser beam is detected by said light detecting means. Detection signal output means for outputting a signal; output signal holding means for temporarily holding an output signal from the light detection means at the time of laser beam detection by the light detection means; output of a detection signal from the detection signal output means Detection data capturing means for capturing the holding signal from the output value holding means as detection data according to the detection data capturing means, wherein the detection data capturing means holds the output value every time a detection signal is output from the detection signal output means. Means for taking in the detection data from the means, and further, an average of a plurality of pieces of detection data taken in by the means for taking in the detection data. The laser drawing apparatus comprising: the average value calculating means for calculating a data, characterized by comprising a conversion means for converting the average value data obtained by said average value calculating means to the light quantity numerical data. 11. A laser writing apparatus according to claim 9, wherein said output value holding means holds a peak value of an output value from said light detection means, and an output value of said peak hold circuit. And an analog / digital converter for converting an analog / digital converter into a digital value, wherein the detection data capturing means captures an output value from the analog / digital converter as detection data. 12. The laser beam drawing apparatus according to claim 11, wherein said detection signal output means comprises a trigger circuit for outputting a trigger signal as a detection signal when said light detection means detects a laser beam. apparatus.