JPH01167719A - Laser beam position correcting device - Google Patents

Abstract

PURPOSE:To simplify beam position correcting operation by installing a beam position detecting means at a position in conjugation relation with the rotational center position of a beam direction changing means, and setting a beam at the rotational center position of the beam direction changing means. CONSTITUTION:A 1st beam direction driving mechanism 12 is driven first to rotate a 2nd reflecting mirror 3 as shown by an arrow and the position of the optical axis of a 1st laser beam 1a is matched with the reference position 18 of a 1st detector 10, thereby moving the optical axis of the 1st laser beam 1a to an ideal position shown by an alternate long and short dash line. Then a 2nd beam direction driving mechanism 13 is driven to rotate a 4th reflecting mirror 5 as shown by an arrow and the position of the optical axis of the 1st laser beam 1a from the 4th reflecting mirror 5 is made coincident with the reference position 20 of a 2nd detector 11 to set the optical axis of the 1st laser beam 1a from the rotational center position 17 of the 4th reflecting mirror 5 to the incidence position 19 on an optical device 7 at the ideal position shown by an original alternate long and short dash line. Consequently, the installation position of the beam position detecting means is corrected with high accuracy.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a laser beam position correction device, and is particularly suitable for a laser beam position correction device when a laser source and an optical device are installed on different tables. The present invention relates to a position correction device.

[Conventional technology]

Conventional laser beam position correction devices are, for example,
As described in Japanese Patent No. 2-Ltt6az, it has been proposed that the beam position detection means are arranged at two different positions on the optical axis behind the two beam direction conversion means when viewed from the laser source.

[Problem that the invention seeks to solve]

The above conventional technology does not consider the installation position of the beam position detection means and the continuous beam position correction of the pulsed laser, resulting in uneven illuminance distribution, complication of beam position correction operation, and correction of the pulsed laser. There was a problem with deterioration of accuracy.

An object of the present invention is to provide a laser beam position correction device that solves the above-mentioned problems of the prior art and can correct the installation position of a beam position detection means and continuously correct the position of a pulsed laser with high precision. It's about doing.

[Means for solving problems]

The above object has a plurality of beam position detecting means and a plurality of beam position detecting means, and has a plurality of beam position detecting means, n counting from the laser source side.
The beam position detecting means t n +1 is arranged at a position conjugate with the rotation center position of the first beam direction changing means, and the last beam position detecting means is arranged at a predetermined position on the optical axis. A laser beam position correcting device characterized in that the direction is sequentially changed by driving a beam direction changing means and the optical axis position of the laser beam can be corrected so as to match the reference position of the beam position detecting means. achieved.

[Operation] In the present invention, since the beam position detection means is installed at a position that is in a conjugate relationship with the rotation center position of the beam direction changing means, the beam is split by the beam splitter and the beam position is adjusted outside the main optical path. This can prevent the illuminance distribution from deteriorating due to optical path blocking.

In addition, when correcting the beam position fMtt, a method is adopted in which the beam position is aligned with the rotation center position of the beam direction changing means, so even if the beam direction changing means in the later stage is driven, the position in the earlier stage is It does not affect the position of the combined beam. Therefore, the beam position correction operation t
- Can be simplified.

Furthermore, it has a second laser beam that can be continuously oscillated with a wavelength different from that of the first laser beam used as an illumination or processing source, and this second laser beam is combined with the first laser beam and its second laser beam. Since the beam position of the first laser beam is corrected by introducing it from the middle of the optical path of the first laser beam so that the leading axes coincide with each other, the position of the first laser beam can be continuously detected. As a result, even if the first laser beam is a laser that oscillates in pulses, the position of the first laser beam can be corrected with high precision.

〔Example〕

Hereinafter, FIG. 1 showing a laser beam position correction device which is an embodiment of the present invention and the second factor will be explained.

As shown in FIG. 1, a first laser beam 1a emitted from a first laser source 1 is transmitted to a plurality of (five in the figure) first laser beams 1a. Second. Third. 1st. Fifth reflector 2. S, 4, 5.6
The direction of the light is sequentially changed by , and the light enters the optical device 7 . Although the configuration of this optical device 7 is omitted, it is, for example, an excimer reduction projection exposure device that uses a laser beam as a light source. In this excimer reduction projection exposure apparatus, if the position or direction of the laser beam incident on the illumination system changes, uneven illuminance or changes in illuminance will occur, adversely affecting the line width and shape of the 15 turns of exposure. Therefore, the incident beam to the illumination system needs to be incident on the optical device 7 at a constant atmospheric pressure position. However, when the first laser source 1 and the optical device 7 are mounted on vibration isolating tables 8 and 9 separately arranged at different positions as in this embodiment, the incident beam is It is difficult to make the light enter a fixed position on the device 7.

Therefore, in the present invention, the first . A second beam position detector 10.11 and a second beam position detector 10.11 and a second beam position detector 10.11 corresponding to a plurality of (two in the figure) beam direction changing means. 3rd reflection @ 5.5f rotating 1st. Second beam direction drive mechanism 12, 15 and CPU 14
are arranged so that the first laser beam 1a from the first laser source is always incident on a fixed position of the optical device 7, and connected to the first laser source 1 by using a wavelength bracket. The second laser beam 15a emitted from the second laser source 15 is
The direction of the optical axis of the laser beam 1a is changed by the sixth reflecting mirror 16, and the laser beam 1a is installed so as to coincide with the optical axis of the first laser beam 1a from the first laser source.

To further explain the above configuration in detail, the 2-even 1st . The second beam detector IQ, 11 is mounted on the same vibration isolation table 9 on which the optical device 7 is mounted, and the two first beam detectors IQ, 11 are mounted on the same vibration isolation table 9 on which the optical device 7 is mounted. The second beam direction drive mechanism 12.15 each has a first laser source 1t.
- The mounted vibration isolation table 8 and the optical device 7t are mounted separately on the mounted vibration isolation table 9. There are also two 1st. Of the second beam detectors 10 and tl, the first detection n10, which is closer to the first laser source 1, is located at the rotation center position 17 of the first reflecting mirror 50, which is rotated by the second beam direction drive mechanism 13 at the subsequent stage.
It is installed at a position 18 in a conjugate relationship with . This position 18 corresponds to the first route from the first laser source 1 to the optical device 7.
It is located off the optical path of the beam 1a. The second laser source 15 is effective when the first laser source 1 oscillates in a pulsed manner, and the second laser beam 15a is direction-changed by the fifth reflecting mirror 4t. It is installed so as to coincide with the first loser beam 1a emitted from the first laser source 1 and whose direction is changed by the first reflecting mirror 2 when the laser beam 1a is turned. Ninth, #11 laser source 1 only
If the position of the laser beam 1a can be corrected, there is no need to install the second laser source 1st.

Next, the operation will be explained with reference to FIGS. 1 and 2.

As shown in FIG.
The beam 1a enters the optical device 7 at a certain position with the optical axis at the ideal position shown by the dashed-dotted line, and on the way there are two third . Two second laser beams 1 branched by the fifth reflecting mirror 4t6
5a'fc each with two 1st. It is assumed that the beam is incident on the reference position &18.20 of the second beam position detector 10.11. However, a case will now be described in which, for some reason, the optical axis of the first loser beam 1a deviates from the ideal position shown by the dashed line and enters the state shown by the broken line.

In this case, in order to return the optical axis of the first loser beam 1a to the ideal position shown by the dotted chain line, the first beam incoming direction drive mechanism 12t is driven and the second reflecting mirror 5't is moved in the direction of the arrow. The optical axis of the second loser beam 1a from the second reflecting mirror 3 is rotated to match the reference position 18 of the first detector 10 (the optical axis at the position indicated by the solid line in FIG. 2). At this time, the amount of rotation of the second reflecting mirror 50 by the first beam direction drive mechanism 12 is
It is calculated by the CPU 14 based on the output of the detector 10.

Next, the second beam direction drive mechanism 13 is driven, and the first reflecting mirror 5'' is rotated in the direction of the arrow Ik to set the position of the optical axis of the first loser beam 1a from the first reflecting mirror 5 to the second detector 110. By matching the position 20, the optical axis of the loser beam 1a from the rotation center position 17 of the first reflecting mirror 5 to the incident position 19 of the optical device 7 can be made to match the original ideal position shown by the dashed line. .

By repeating this operation at regular intervals, the optical axis of the first loser beam 1a can always be made incident on the constant position 19 of the optical device 7.

Next, a laser beam position correcting device which is another embodiment of the present invention will be explained with reference to FIG.

In the laser beam position correction device shown in FIG. 3, the second beam position detector 11 is installed at the same position as in the embodiment shown in FIGS. The fifth reflection mirror m
4t - This is the case when omitted.

Further, in the laser beam position correcting device which is still another embodiment of the present invention shown in FIG.
Second laser beam 15ai transmitted and direction-changed at seventh semi-transparent @22 Reference position 2 of second beam position detector 11
0, and is incident on the first beam position detector 100 reference position 1B via the semi-transparent mirror 22t - the transmitted second laser beam 15aii - the imaging lens 21, and in this case also the fifth reflecting mirror 4t -Omitted.

Therefore, as is clear from these embodiments, in the laser beam position correction device according to the present invention, the beam position detector is installed at a position outside the main optical path of the first laser beam, and the reflecting mirror is controlled by the beam direction driving mechanism. A second laser beam whose wavelength is different from that of the second laser beam at the position t-co of the first laser beam emitted from the first laser source is simplified.
A constant correction can be provided by a second laser beam emitted from the laser source.

〔Effect of the invention〕

According to the present invention, since the beam position detecting means is installed on the beam direction changing means at a position that is conjugate with the rotation center position of the beam direction changing means, the beam is split by the beam splitter, and the beam is split off from the main optical path. It becomes possible to detect the position of the beam, thereby preventing deterioration of the illuminance distribution due to optical path blocking.

9. When correcting the beam position, a method is adopted in which the beam position is aligned with the rotation center position of the beam direction changing means. It does not affect the position of the combined beam. Therefore, the beam position correction jEllft
i'.

Furthermore, it has a second laser beam that can be continuously oscillated with a different wavelength from the first laser beam used as an illumination or processing source, and this second laser beam is used as a light source for the first laser beam and the first laser beam. Since the beam position of the first laser beam is corrected by introducing it from the middle of the optical path of the first laser beam so that the axes coincide with each other,
The position of the first laser beam can be continuously detected,
Thereby, even if the first laser beam is a laser that oscillates in a pulsed manner, the alignment of the first laser beam can be corrected with high precision.

[Brief explanation of the drawing]

FIG. 1 shows the overall configuration of a laser beam position correction device that is an embodiment of the present invention, FIG. 2 is an explanatory diagram of its operation, and FIG.
This figure is an explanatory diagram of the operation of a laser beam position correcting device which is another embodiment of the present invention, and the 100th figure is an explanatory diagram of the operation of a laser beam position correcting device which is still another embodiment of the present invention. 1... Laser source? ~6... Reflector, 7... Optical device, 8.9... Vibration isolation table, 10.11... Beam position detector, 12.15... Beam direction drive mechanism, 14
...cpu.

Claims (1)

[Claims] 1. It has a plurality of beam position detecting means and a plurality of beam direction changing means, and the nth beam position detecting means counting from the laser source side is the n+1th beam direction changing means. The last beam position detecting means is placed at a predetermined position on the optical axis, and the direction of the laser beam from the laser source is sequentially changed by the beam direction changing means to change the direction of the laser beam. 1. A laser beam position correction device, characterized in that the laser beam position correction device is configured to correct the position of the optical axis of the laser beam so as to match the reference position of the beam position detection means. 2. The beam position detection means detects a laser beam from a laser source installed separately from the laser source, with a wavelength different from that of the laser beam, so that the optical axis of the laser beam coincides with the optical axis of the laser beam from the middle of the optical path of the laser beam. 2. The laser beam position correction device according to claim 1, wherein the second laser beam is used to detect the position of the optical axis of the laser beam.