JPH05325269A - Exposure device - Google Patents

Abstract

PURPOSE:To reduce the man-hour of quality check by keeping the diameter of an exposure beam constant at the time of exposing an optical disk original with a laser beam and reducing the variance of products among lots to improve the quality of products. CONSTITUTION:When a laser beam 8 whose power is controlled is inputted to an optical modulation part 2, modulation is performed in accordance with a modulation signal 15, and an obtained modulated beam 9 is outputted to a beam diameter adjusting part 3. This part 3 extends the diameter of the beam 9 and outputs a diameter-adjusted beam 13 to an optical head part 4. The optical head part 4 condenses the beam 13 by a focus servo means or the like, and a beam diameter measuring part 5 is irradiated with an exposure beam 14. Thereafter, a beam diameter signal 11 obtained by measurement is inputted to a beam diameter correcting part 6, and the signal 11 and a set value signal 10 from a set storage part 7 are compared with each other in this part 6 to calculate the beam diameter, and a correction value signal 12 corresponding to the calculated correction value is given to the adjusting part 3, and the diameter of the modulated beam 9 from the optical modulation part 2 is adjusted, and the processing is repeated till the correction value is 0.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus, and more particularly to an exposure apparatus suitable for exposing an optical disc master with a laser beam.

[0002]

2. Description of the Related Art FIG. 2 shows a conventional example. In the conventional example shown in FIG. 2, an optical modulator 22 for optically modulating a laser beam 25, an expander 23 for expanding the beam diameter of a modulated beam 26 output from the optical modulator 22, and an expander 23 are provided. And an optical head section 24 for converging an expanded beam 28 having an expanded beam diameter to irradiate the surface of the object 21.

The optical modulator 22 is composed of, for example, an A / O modulator or an E / O modulator, and applies a modulation signal 27 to the terminal 101 as a drive input of a driver of the modulator.

Next, the operation of the above conventional example will be described. ． When the power-controlled laser beam 25 is input, the optical modulation unit 22 modulates the laser beam 25 according to the modulation signal 27 input from the terminal 101, and outputs the modulated beam 26 to the expander unit 23. Here, the groove is exposed by giving an ON signal to the light modulator 22 as the modulation signal 27, and the pit is exposed by giving an ON-OFF signal.

.. The expander unit 23 includes the light modulation unit 22.
The beam diameter of the modulated beam 26 is expanded and output to the optical head unit 24.

[0006]. The optical head unit 24 is the expander unit 2
The expanded beam 28 from 3 is condensed by the focus servo means to be an exposure beam.

[0007]. Then, the object 21 is rotated, and at the same time, the exposure beam 29 from the optical head portion 24 is controlled by a rotation moving mechanism (not shown) so that the exposure beam 29 moves on the object 21 from the inner circumference to the outer circumference. I was exposing.

[0008]

However, in the above-mentioned conventional example, since the beam diameter of the exposure beam from the optical head cannot be measured, there are many variations in groove and pit dimensions between manufacturing lots, and the development is difficult. There is a disadvantage that the grooves and pits of the object are to be observed later with an electron microscope or the like, and the exposure apparatus must be adjusted based on the result to perform the exposure process again.

[0009]

SUMMARY OF THE INVENTION The object of the present invention is to improve the disadvantages of the conventional example, and in particular, in the exposure of an optical disk master by a laser beam, the exposure beam diameter can be kept constant, and the lot-to-lot variation of the product is small, Moreover, it is an object of the present invention to provide an exposure apparatus which can stably obtain high quality products and can significantly reduce the number of quality check steps.

[0010]

Therefore, in the present invention, an optical modulator for optically modulating a laser beam based on a modulation signal and a beam diameter adjustment for adjusting the beam diameter of a modulated beam output from the optical modulator. Section, an optical head section that collects the diameter adjustment beam output from this beam diameter adjustment section and outputs it as an exposure beam, and a beam diameter measurement section that measures the beam diameter of the exposure beam output from this optical head section. , A beam diameter correction amount is calculated from a beam value signal from a beam value measuring unit and a beam value signal from the beam diameter measuring unit, and a beam value measuring unit that stores a preset beam diameter value. A configuration is provided that includes a beam diameter correction unit that outputs a correction amount signal corresponding to this correction amount to the beam diameter adjustment unit. This aims to achieve the above-mentioned object.

[0011]

When the laser beam is input, the light modulating section modulates the laser beam according to the modulation signal and outputs the modulated beam to the beam diameter adjusting section. The beam diameter adjusting unit expands the diameter of the modulated beam from the light modulating unit and outputs it as a diameter adjusting beam to the optical head unit. The optical head unit collects the diameter adjusting beam from the beam diameter adjusting unit by a focus servo unit or the like, and irradiates the beam diameter measuring unit as an exposure beam.

The beam diameter measuring unit measures the beam diameter of the exposure beam from the optical head unit and outputs it as a beam diameter signal to the beam diameter correcting unit. The beam diameter correction unit calculates the correction amount of the beam diameter by comparing the beam diameter signal from the beam diameter measurement unit with the set value signal from the set value storage unit, and the correction amount corresponding to this calculated correction amount. The signal is output to the beam diameter adjustment unit.

The beam diameter adjusting section adjusts the diameter of the modulated beam from the light modulating section according to the correction amount signal from the beam diameter correcting section. Then, the adjusted beam is output to the optical head section as a diameter adjustment beam. Then, the above processing is repeated until the correction amount in the beam diameter correction unit becomes zero.

When the focused beam diameter on the beam diameter measuring section reaches a desired value, the rotary moving mechanism moves the optical head section onto the object and rotates the object. Further, the optical head unit is controlled so that the exposure beam is irradiated onto the object from the inner circumference toward the outer circumference, and spiral exposure is performed.

[0015]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described below with reference to FIG. In the embodiment of FIG. 1, an optical modulator 2 that optically modulates a laser beam 8 based on a modulation signal 15, and a beam diameter adjuster 3 that adjusts the beam diameter of a modulated beam 9 output from the optical modulator 2. , An optical head unit 4 for condensing the diameter adjusting beam 13 output from the beam diameter adjusting unit 3 and outputting it as an exposure beam 14, and a beam diameter for measuring the beam diameter of the exposure beam 14 output from the optical head unit 4. Measuring part 5
Of the beam diameter from the set value storage unit 7 in which the preset value of the beam diameter is stored, the beam diameter signal 11 from the beam diameter measuring unit 5 and the set value signal 10 from the set value storage unit 7. The beam diameter correction unit 6 calculates a correction amount and outputs a correction amount signal 12 corresponding to the correction amount to the beam diameter adjustment unit 3.

The optical modulator 12 is composed of, for example, an A / O modulator or an E / O modulator, and the modulation signal 15 is input as a drive input of a driver of the modulator.

The beam diameter measuring section 5 is, for example, a PHOT.
The data of the half-value width of the beam diameter measured from the intensity distribution of the exposure beam 14 is output as the beam diameter signal 11 like “Spot Scan” manufactured by ON.

Further, the beam diameter adjusting section 3 uses a piezo element for adjusting the position of the incident side lens in the conventional expander, and the correction amount signal 1 from the beam diameter correcting section 6 is used.
By using 2 as a drive signal for the piezo element, it is possible to finely move the position of the incident side lens and adjust the beam diameter.

Next, the operation of this embodiment will be described. ． When the power-controlled laser beam 8 is input, the optical modulator 2 modulates the laser beam 8 according to the input modulation signal 15, and outputs the modulated beam 9 to the beam diameter adjuster 3.

Here, the groove is exposed by applying an ON signal to the optical modulator 2 as the modulation signal 15 and the pit is exposed by applying an ON-OFF signal.

[0021]. The beam diameter adjusting unit 3 expands the diameter of the modulated beam 9 from the light modulating unit 2 and outputs it as a diameter adjusting beam 13 to the optical head unit 4.

.. The optical head unit 4 collects the diameter adjusting beam 13 from the beam diameter adjusting unit 3 by a focus servo means or the like, and irradiates the beam diameter measuring unit 5 as an exposure beam 14.

.. The beam diameter measuring unit 5 measures the beam diameter of the exposure beam 14 from the optical head unit 4 to obtain a beam diameter signal 1
It is output to the beam diameter correction unit 6 as 1.

[0024]. The beam diameter correction unit 6 compares the beam diameter signal 11 from the beam diameter measurement unit 5 with the set value signal 10 from the set value storage unit 7 to calculate the correction amount of the beam diameter,
The correction amount signal 12 corresponding to the calculated correction amount is output to the beam diameter adjusting unit 3.

[0025]. The beam diameter adjusting unit 3 adjusts the diameter of the modulated beam 9 from the light modulating unit 2 according to the correction amount signal 12 from the beam diameter correcting unit 6. Then, the adjusted beam is output to the optical head unit 4 as the diameter adjusting beam 13.
Then, the above processes 1 to 3 are repeated until the correction amount in the beam diameter correction unit 6 becomes zero.

.. When the focused beam diameter on the beam diameter measuring unit 5 reaches a desired value, the control means (not shown) drives the rotation moving mechanism to move the optical head unit 4 onto the object 1 and rotate the object 1. ..

[0027]. Further, the control means controls the rotational movement mechanism so that the exposure beam 14 exposes the object 1 from the inner circumference toward the outer circumference, and performs the spiral exposure.

In exposing the groove or pit,
Since the beam diameter collected by the optical head unit 4 is controlled by the beam diameter measuring unit 5 and has a desired value, stable grooves or pits can be exposed without performing check exposure.

[0029]

Since the present invention is constructed and functions as described above, the diameter of the exposure beam from the optical head can be kept constant according to the present invention. It is possible to provide an unprecedented excellent exposure apparatus that can stably obtain high-quality products and can significantly reduce the number of quality check steps.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a conventional example.

[Explanation of symbols]

 1 Object 2 Optical Modulation Section 3 Beam Diameter Adjustment Section 4 Optical Head Section 5 Beam Diameter Measurement Section 6 Beam Diameter Correction Section 7 Setting Value Storage Section 8 Laser Beam 9 Modulated Beam 10 Setting Value Signal 11 Beam Diameter Signal 12 Correction Amount Signal 13 Diameter adjustment beam 14 Exposure beam 15 Modulation signal

Claims (1)

[Claims] 1. An exposure apparatus comprising: an optical modulator for optically modulating a laser beam based on a modulation signal; and an optical head unit for converging the light-modulated beam and irradiating an object with the optical modulator. Beam diameter adjusting section for adjusting the beam diameter of the modulated beam output from the optical head section according to a correction amount signal and outputting it to the optical head section, and a beam diameter measuring section for measuring the beam diameter of the exposure beam output from the optical head section. And a set value storage unit that stores a preset beam diameter value, and a beam diameter correction amount from a beam diameter signal from the beam diameter measuring unit and a set value signal from the set value storage unit. An exposure apparatus comprising: a beam diameter correcting unit that calculates and outputs a correction amount signal corresponding to the correction amount to the beam diameter adjusting unit.