JPH07202307A - Laser generator - Google Patents

Abstract

PURPOSE:To provide a laser generator which is preferably applicable to various laser application devices utilizing a plurality of laser light individually modulat ed. CONSTITUTION:A plurality of laser oscillators 15 which can generate laser light and directly modulate the laser light inside are provided, wherein an end of an optical fiber 16 is connected to the output ends of the laser oscillators 15, 15,... while other ends of the optical fibers 16 are arranged by a ferrule 17 or the like to be integrated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser generator suitable for application to various laser application devices such as a laser drawing device that individually modulate and use a plurality of laser beams.

[0002]

2. Description of the Related Art In recent years, in the field of miniaturization of semiconductors, as a photolithography technique which is one of manufacturing processes, in addition to the conventional pattern transfer method using a photomask, a pattern is directly formed on a resist film by using a laser or the like. A direct drawing method for drawing is drawing attention. Then, the laser drawing apparatus used in this method generates a plurality of laser beams inside the apparatus and individually modulates each laser beam to superpose drawing data, and then these laser beams are applied to the resist film. The pattern is directly drawn by irradiation.

FIG. 2 is a diagram showing an example of the laser drawing apparatus 1. The laser light emitted from the laser oscillator 2 is branched into eight laser lights by the beam splitter 3, and these eight laser lights are emitted by the acousto-optic modulator 4 (Acousto-Optic).
A laser beam is incident on a modulator (hereinafter referred to as AOM), and each laser beam is individually modulated, so that drawing data for each laser beam is superimposed as a signal. AOM4
The laser beam that has passed through is reflected by the steering mirror 5, transmitted through the zoom lens 6, and then scanned by the polygon 7 (rotating polygon mirror). Further, the laser beam scanned by the polygon 7 passes through the f-θ lens 8 and the image splitter 9, is converged by the objective lens 10 and is irradiated on the sample 12 mounted on the stage 11, for example, the resist film on the photomask. Then, the pattern is drawn.

[0004]

However, in the conventional laser drawing apparatus 1, the laser oscillator 2 to the AOM 4 for generating and branching laser light and modulating each laser light are used.
In the above part, various problems as described below have occurred.

First, when one laser beam emitted from the laser oscillator 2 is branched into eight beams, the power of each laser beam becomes ⅛, and this branched laser beam is finally the sample 12. Therefore, the power of the laser beam after branching must be a predetermined value, that is, a value above which the resist can be exposed. Therefore, in order to maintain the power of the laser light after branching at a predetermined value or more, the laser light before branching is
It is necessary to have at least eight times as high a power as the resist can be exposed to light, and for example, a large-sized and high-power laser oscillator 2 having a length of 1.3 m in the optical axis direction and an output of 5 W was necessary. However, the large-sized, high-power laser oscillator 2 is not only large in size but also requires a large-capacity cooling device due to the large amount of heat generation, which makes the entire laser drawing device 1 very large and has a large installation space. Was needed.

Further, since the laser oscillator 2 has a large output as described above, the life of the laser oscillator 2 is relatively short,
It was necessary to replace the laser oscillator 2 frequently.

Further, when splitting one laser beam into eight beams by the beam splitter 3, it is difficult to disperse the power of the laser beam evenly by ⅛, and at the same time, the laser beam is split by the beam splitter 3. Was being lost. Further, the AOM 4 at the next stage of the beam splitter 3
However, since the loss of the laser beam occurs, the transmission efficiency of the laser beam was considerably lowered by transmitting the laser beam to the beam splitter 3 and the AOM 4. Therefore, it is necessary to further increase the power of the laser oscillator 2 in consideration of the loss of the laser light.

Further, the beam splitter 3 has three mirrors inside, and by combining these mirrors, one laser beam is branched into two, four, and eight in three steps. In order to accurately align the laser light of (1) at a predetermined interval, it is necessary to adjust the positions and angles of these mirrors very precisely, which is a difficult task.

The present invention has been made to solve the above problems, and is applied to various laser application devices such as a laser drawing device that individually modulate and use a plurality of laser beams. It is an object of the present invention to provide a suitable laser generator.

[0010]

In order to achieve the above-mentioned object, the laser generator of the present invention includes a plurality of laser oscillators capable of generating laser light and directly internally modulating the laser light. , One end of an optical fiber is connected to each of the output ends of the plurality of laser oscillators, and the other ends of the plurality of optical fibers are aligned so that their end faces are flush with each other. The other end is integrated.

[0011]

In the laser generator of the present invention, each of the plurality of laser oscillators generates laser light,
Each emits independently modulated laser light. Then, each laser beam emitted from the laser oscillator is transmitted through the optical fiber and emitted from the end of the optical fiber opposite to the laser oscillator. At this time, since the end faces of the optical fiber are aligned, a plurality of laser lights are aligned and emitted from the end.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the laser generator of the present invention will be described below with reference to FIG. Laser generator A of this embodiment
Is applied to the laser drawing apparatus shown as the conventional technique, and in FIG. 1, the same reference numerals are given to the components common to the conventional laser drawing apparatus.

FIG. 1 is a diagram showing the basic configuration of the entire laser drawing apparatus 14, in which reference numeral A is a laser generator, B is an optical module including various optical elements, 12 is a sample, and the like. A control unit (not shown) is provided.

In the laser generator A, eight laser oscillators 15, 15, ..., An optical fiber 16 connected to each laser oscillator 15, and eight optical fibers 16, 16 ,. And a ferrule 17 for performing the operation.

This laser oscillator 15 mixes a semiconductor laser light with a Nd: YAG laser fundamental wave in a crystal,
A short wavelength light of 364 nm can be emitted by the sum frequency generation, and by directly modulating the semiconductor laser light to be mixed, high speed modulation of the laser light generated inside the laser oscillator 15, for example, switching of about 5 to 6 nsec can be performed. You can do it. Eight such laser oscillators 15 are installed in parallel, and the output ends of these laser oscillators 15, 15, ... Are connected to one end of optical fibers 16, 16 ,. The other end of each optical fiber 16 is fixed to the ferrule 17, and the side faces of each ferrule 17 are joined together so that the eight end faces of the optical fiber 16 are aligned so as to be flush with each other. It is integrated. Then, the integrated ferrule 17 is installed in the preceding stage of the optical module B in the laser drawing apparatus 14 by a supporting member (not shown).

On the other hand, the optical module B comprises a steering mirror 5, a zoom lens 6, a polygon 7, an f-θ lens 8, an image splitter 9, an objective lens 10 and a stage 11.

That is, the laser drawing apparatus 14 is obtained by replacing the laser oscillator 2, the beam splitter 3, and the AOM 4 which are the constituent elements of the conventional laser drawing apparatus 1 with the laser generator A of this embodiment. That is,
In place of the laser oscillator 2 in the conventional apparatus, the eight laser oscillators 15, 15, ... Are provided, and the beam splitter 3 and the AOM 4 in the conventional apparatus are omitted, and a ferrule 17 integrated in front of the steering mirror 5 is provided. It has been installed.

In the laser drawing apparatus 14 having the above structure, first, the laser generator A generates eight laser beams. Here, in response to the drawing data signal from the control unit, each of the eight laser oscillators 15, 15, ... Independently performs high-speed modulation therein, and generates a 364 nm laser beam. Then, the generated laser light is transmitted through the optical fiber 16 from the output end of the laser oscillator 15, and eight laser lights are emitted from the end fixed to the ferrule 17 in a state of being aligned at regular intervals. Therefore, the eight laser beams are incident on the optical module B in the next stage in a state where the drawing data for each laser beam is superimposed.

Next, the laser light emitted from the laser generator A is reflected by the steering mirror 5, transmitted through the zoom lens 6, and scanned by the polygon 7 (rotating polygon mirror). Further, the laser beam scanned by the polygon 7 passes through the f-θ lens 8 and the image splitter 9, is converged by the objective lens 10 and is formed on the resist film on the sample 12 (photomask) mounted on the stage 11 as a resist film. Irradiation is performed and a pattern is drawn.

In this laser drawing apparatus 14, the laser generator A is provided with eight laser oscillators 15, 15, ... In parallel, and the laser light emitted from these laser oscillators 15, 15 ,. Since the laser beam emitted from the laser oscillator 15 has a power enough to sensitize the resist because the sample 12 is irradiated without the laser beam, a laser having a power more than 8 times the value that can sensitize the resist. The laser oscillator 15 can be made smaller and have a smaller output as compared with the conventional case where an oscillator is required. Further, since the small-sized and small-output laser oscillator 15 has a small amount of heat generation, it is possible to eliminate the need for a cooling device. As described above, the laser drawing apparatus 14 does not require the beam splitter 3 and the AOM 4, so that the large laser oscillator 2, the cooling device, the beam splitter 3, and the AOM 4 in the conventional apparatus are all unnecessary, and the laser drawing apparatus 14 as a whole. Can be extremely miniaturized and simplified. Therefore, the laser drawing device 14
Installation space is small and maintenance, inspection,
Maintenance can be performed easily. Also, the cost of the laser drawing device 14 can be reduced.

Further, since the laser oscillator 15 has a small output, it has a longer life than the conventional laser oscillator. Therefore, the frequency of exchanging the laser oscillator 15 can be reduced.

Further, since the beam splitter 3 and the AOM 4 which cause a loss of laser light by transmitting the inside can be omitted, compared with the conventional laser drawing apparatus,
The propagation efficiency of laser light can be improved.

Further, by fixing the optical fiber 16 connected to each laser oscillator 15 to the ferrule 17, the eight optical fibers 16, 16, ... Can be arranged at regular intervals and with their end faces aligned. Therefore, the alignment of the laser light can be performed easily and surely as compared with the conventional case that requires a fine adjustment of the mirror in the beam splitter 3.

In the present embodiment, eight laser oscillators 15, 15, ... Are installed in the laser generator A to emit eight laser beams, but the number of laser oscillators 15 is not limited to the above. It does not need to be limited to this and can be arbitrary. In the conventional laser drawing apparatus 1, since one laser beam is branched into two, four, ... With the combination of the mirrors in the beam splitter 3, the number of laser beams to be generated is naturally determined. Against
In the case of this embodiment, the number of laser beams to be generated can be set freely. Further, regarding the method of aligning the optical fibers 16, the ferrule 17 in this embodiment is used.
In addition to the fixing by the above method, it is also possible to perform various methods such as fusion bonding of the side surfaces of the optical fiber 16 without using the ferrule 17. Then, in the present embodiment, an example in which the laser generation device is applied to a laser drawing device has been described, but in addition to this, for example, the laser generation device is applied to various laser application devices such as an optical communication system using a laser. It is possible to apply.

[0025]

As described above in detail, since the laser generator of the present invention is provided with a plurality of laser oscillators capable of directly performing internal modulation, a plurality of laser beams are individually modulated. When it is applied to various laser application devices that are used as a laser, it is possible to eliminate the need for a device for branching or modulating laser light. Further, since the laser light is not branched, each laser oscillator only needs to have the minimum power required for various functions of the laser application device, so that the laser oscillator itself can be downsized and output small. it can. Therefore, these configurations can downsize and simplify the entire laser application apparatus. Further, since the laser oscillator has a small output, its life is extended, so that the frequency of replacement of the laser oscillator can be reduced. further,
One end of the optical fiber is connected to each of the plurality of laser oscillators, and the other end side is configured such that its end faces are aligned and integrated, so for example, delicate adjustment work in various equipment such as a beam splitter. The laser light can be easily aligned without performing the above.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a laser drawing apparatus to which a laser generator according to an embodiment of the present invention is applied.

FIG. 2 is a diagram showing a configuration of a conventional general laser drawing apparatus.

[Explanation of symbols]

 A laser generator 14 laser drawing device 15 laser oscillator 16 optical fiber 17 ferrule

Claims (1)

[Claims] 1. A laser generator for generating a plurality of independently modulated laser beams in parallel, the laser generator generating a laser beam and directly modulating the laser beam internally. A plurality of operable laser oscillators are provided, one end of each optical fiber is connected to the output end of each of the plurality of laser oscillators, and the end faces of the other ends of the plurality of optical fibers are flush with each other. The laser generator is characterized in that the other ends are integrated.