CN209860346U

CN209860346U - Wavelength tuning device based on precision rotary table

Info

Publication number: CN209860346U
Application number: CN201920780408.3U
Authority: CN
Inventors: 张海波; 周军; 杨军红; 江锐; 袁志军; 沙鹏飞; 韩晓泉; 陈刚
Original assignee: Naijing Zhongke Shenguang Technology Co Ltd; Beijing Keyihongyuan Photoelectric Technology Co Ltd
Current assignee: Naijing Zhongke Shenguang Technology Co Ltd; Beijing Keyihongyuan Photoelectric Technology Co Ltd
Priority date: 2019-05-28
Filing date: 2019-05-28
Publication date: 2019-12-27
Anticipated expiration: 2029-05-28

Abstract

The utility model relates to a laser technical field provides a wavelength tuning device based on accurate revolving stage, and the device includes: the device comprises a slit, a prism beam expanding module, a precision turntable, a high reflector and a diffraction grating, wherein the high reflector and the diffraction grating are arranged on the precision turntable; the laser beam passes through the slit and then enters the prism beam expanding module for one-dimensional beam expansion to form a beam expanded laser beam; the expanded laser beam is reflected by a high reflector to form a reflected beam; the reflected beam is incident on the grating for diffraction at the blaze angle of the diffraction grating to form a diffracted beam which is reversely coincident with the reflected beam; the diffracted light beams are emitted after sequentially passing through the high reflector, the prism beam expanding module and the slit. The wavelength tuning device provided by the utility model realizes tuning the central wavelength of the laser by rotating the high reflector, and has simple operation and high tuning precision; meanwhile, the device avoids the influence of turbulence caused by rotating the grating on the laser spectrum and the problem that the rotating prism can reduce the laser efficiency.

Description

Wavelength tuning device based on precision rotary table

Technical Field

The utility model relates to a laser technical field, more specifically say, relate to a wavelength tuning device based on accurate revolving stage.

Background

In the high-end photoetching field, the high repetition frequency excimer laser is an absolutely dominant light source applied in the semiconductor photoetching field at present due to the characteristics of high repetition frequency, narrow line width and large energy. In the lithography application, not only the accurate tunable output of the laser wavelength is realized according to the requirement, but also the wavelength drift caused by vibration, temperature change and the like is required to perform feedback control in order to improve the stability of the laser output center wavelength, and the long-time dynamic stability of the laser wavelength is tuned through closed-loop control. Since the tuning accuracy needs to be of the order of 0.01pm, the accuracy and response speed of the tuning are extremely high.

For this, the laser wavelength is generally tuned by means of a tuning prism or a grating. However, the tuning prism needs a plurality of prisms to tune simultaneously, the synchronization control difficulty is high, and when the wavelength tuning range is large, the deviation angle of the emergent light spot direction of the prism beam expander is increased, so that the position of laser incident on the grating is influenced, and the efficiency of the laser is reduced. On the other hand, the laser wavelength is tuned by rotating the grating in a direct manner, but the laser spectrum is greatly affected, and the bandwidth of the laser spectrum, the spectrum waveform and the symmetry are deteriorated by aerodynamic disturbance or changes of clean air flow generated during rotation.

SUMMERY OF THE UTILITY MODEL

In view of the above problem, the utility model provides an increase high speculum between prism beam expanding module and grating, on accurate revolving stage was located to high speculum, realized carrying out harmonious technical scheme to the central wavelength of laser through rotating high speculum.

The purpose of the utility model can be realized by the following technical measures:

the utility model provides a wavelength tuning device based on accurate revolving stage, the device includes:

a slit for intercepting a central portion of the laser beam to effectively control a beam divergence angle;

the prism beam expanding module is used for carrying out one-dimensional beam expansion on the laser beam after passing through the slit so as to form a beam expanded laser beam;

the high reflector is used for reflecting the beam expanding laser beam to form a reflected beam; the high reflector rotates along with the precision rotary table to adjust the incident angle of the expanded beam laser beam;

a diffraction grating making up a littrow structure with the reflected beam, diffracting the reflected beam to form a diffracted beam;

and the diffracted light beams are emitted after sequentially passing through the high reflector, the prism beam expanding module and the slit.

Preferably, the central axis of the reflecting surface of the high-speed reflector coincides with the rotating shaft of the precision turntable.

Preferably, a spot of the expanded beam is incident on a center position of the high reflection mirror.

Preferably, the rotation precision of the precision rotary table is less than or equal to 0.1 μ rad.

More preferably, the precision turntable is a PZT nano-turntable.

Preferably, the diffraction grating is an echelle grating.

More preferably, the blaze angle of the echelle grating is 71-82 degrees; and/or

The grating constant of the echelle grating is 1/94.13 mm.

Preferably, the prism beam expanding module is formed by sequentially arranging a plurality of right-angle prisms.

Preferably, the chord surface of the right-angle prism is plated with an antireflection film.

Preferably, the wavelength tuning precision of the device is 0.003-0.005 pm.

Compared with the prior art, the middle and high reflecting mirrors in the wavelength tuning device provided by the utility model are reflecting elements, the size is relatively small, and the requirements on the load and the size of the rotary table are reduced; the center wavelength of the laser is tuned by rotating the high-reflection mirror, so that the operation is simple and the tuning precision is high; under the rotation error of the rotary table, the driving and the control in the tuning process are convenient, the response time of tuning is improved, and the dynamic stability of the central wavelength of the laser is improved; meanwhile, the device avoids the influence of turbulence caused by rotating the grating on the laser spectrum and the problem that the rotating prism can reduce the laser efficiency.

Drawings

Fig. 1 is a schematic view of a wavelength tuning apparatus based on a precision turntable according to an embodiment of the present invention.

In the figure: 1. a slit; 2. a prism beam expanding module; 3. a precision turntable; 4. a high reflection mirror; 5. a diffraction grating; 6-9 and a right-angle prism.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In order to make the description of the present disclosure more complete and complete, the following description is given for illustrative purposes with respect to the embodiments and specific examples of the present invention; it is not intended to be the only form in which the embodiments of the invention may be practiced or utilized. The embodiments are intended to cover the features of the various embodiments as well as the method steps and sequences for constructing and operating the embodiments. However, other embodiments may be utilized to achieve the same or equivalent functions and step sequences.

The utility model provides a wavelength tuning device based on accurate revolving stage, please refer to and show in fig. 1, the device includes slit 1, prism beam expanding module 2, accurate revolving stage 3 and locate high-reflecting mirror 4, diffraction grating 5 on this accurate revolving stage 3, slit 1 is used for intercepting the central part of laser beam with effective control light beam divergence angle to tune the central wavelength of laser, control stray light entering tuning device, in order to reduce the influence of stray light to tuning device; the size of the diffraction grating can be controlled, and the size and the cost of the device can be reduced; according to some embodiments of the present invention, the width of the slit 1 is 1mm to 2 mm. The laser beam passes through the slit 1 and then enters the prism beam expanding module 2 to perform one-dimensional beam expansion to form an expanded beam laser beam, the expanded beam laser beam reaches the high reflector 4 and then is reflected to form a reflected beam, the diffraction grating 5 and the reflected beam form a littrow structure, namely, the reflected beam can be incident at a blaze angle of the diffraction grating 5, and the diffracted beam meeting the diffraction grating equation returns along an original optical path, namely is reversely coincided with the reflected beam, and then is emitted after sequentially passing through the high reflector 4, the prism beam expanding module 2 and the slit 1.

In order to improve the tuning precision of laser center wavelength the utility model discloses an in some embodiments, coincide the central axis of the plane of reflection of high speculum 4 and precision turntable 3's pivot, and the facula of the laser beam of expanding the beam incides the central point of high speculum 4 and puts.

According to some embodiments of the present invention, the rotation precision of the precision turntable 3 is less than or equal to 0.1 μ rad, and any suitable precision turntable in the field can be selected, for example, a PZT nano turntable, which includes a piezoelectric ceramic driver and a controller, and can control the rotation precision at less than or equal to 0.1 μ rad.

According to the utility model discloses a some embodiments, prism beam expanding module 2 is arranged in proper order by a plurality of right angle prisms and is constituteed, and the light beam incides the chord face of each prism in proper order and through the outgoing of the right angle face that corresponds, and the angle that the adjustment light beam incided the prism can adjust the beam expanding multiplying power of beam expanding module. Meanwhile, in order to reduce the light loss formed by Fresnel reflection among the prisms, antireflection films are arranged on the right-angle prisms. In other embodiments of the present invention, the number of right-angle prisms is preferably 2-4, for example, in this embodiment, the prism beam expanding module 2 is composed of 4 triangular prisms 6, 7, 8, and 9.

According to the utility model discloses a some embodiments, diffraction grating 5 is echelle grating, and its surface needs to plate the high membrane of reflecting in order to reduce the photoelectricity that the incident light caused and to leave the damage, and this echelle grating's blaze angle is 71 ~ 82, and the grating constant is 1/94.13 mm.

The utility model discloses in, the littrow structure has been constituteed with diffraction grating 5 to the reflected beam that forms through the high-reflecting mirror reflection, and the incident angle (the blaze angle of diffraction grating 5 promptly) that this reflected beam incides on the diffraction grating 5 equals with the diffraction angle of the diffraction beam of production promptly, and the grating equation can be written as formula (1) and show:

2d sinβ＝kλ (1)

wherein d is a grating constant, β is a grating blaze angle, and k is a diffraction order. Differentiating the formula (1) to obtain a formula (2):

2d cosβdβ＝kdλ (2)

d β represents the rotation accuracy of the precision turntable 3, and therefore, the wavelength tuning accuracy of the tuning device provided by the present invention is represented by formula (3):

according to the formula (3), the wavelength tuning precision of the device can be estimated to be 0.003-0.005 pm.

The high reflector in the wavelength tuning device is a reflecting element, the size is relatively small, and the requirements on the load and the size of the rotary table are reduced; the center wavelength of the laser is tuned by rotating the high-reflection mirror, so that the operation is simple and the tuning precision is high; under the rotation error of the rotary table, the driving and the control in the tuning process are convenient, the response time of tuning is improved, and the dynamic stability of the central wavelength of the laser is improved; meanwhile, the device avoids the influence of turbulence caused by rotating the grating on the laser spectrum and the problem that the rotating prism can reduce the laser efficiency.

The first embodiment is as follows:

when the blaze angle β and the grating constant d of the diffraction grating 5 are 79 ° and 1/94.13mm, respectively, the diffraction order k of the grating at a wavelength of 193.4nm is 108 as calculated from the formula (1); if the rotation accuracy of the precision turret 3 is 0.1 μ rad, the wavelength tuning accuracy of the apparatus is 0.00375pm as calculated from the equation (3).

The above description is only exemplary of the present invention and should not be taken as limiting the scope of the present invention, as any modifications, equivalents, improvements and the like made within the spirit and principles of the present invention are intended to be included within the scope of the present invention.

Claims

1. A wavelength tuning apparatus based on a precision turret, comprising:

2. The wavelength tuning apparatus of claim 1, wherein a central axis of the reflecting surface of said high-reflection mirror coincides with a rotation axis of said precision turret.

3. The wavelength tuning device of claim 1, wherein the spot of the expanded beam is incident on a central location of the high-reflectivity mirror.

4. The wavelength tuning device of claim 2, wherein the precision turret has a rotational precision of 0.1 μ rad or less.

5. The wavelength tuning apparatus of claim 4, wherein said precision turret is a PZT nanostar.

6. The wavelength tuning device of claim 1, wherein the diffraction grating is an echelle grating.

7. The wavelength tuning device of claim 6, wherein a blaze angle of the echelle grating is 71 to 82 °; and/or

The grating constant of the echelle grating is 1/94.13 mm.

8. The wavelength tuning device of claim 1, wherein the prism beam expanding module is formed by sequentially arranging a plurality of right-angle prisms.

9. The wavelength tuning device of claim 8, wherein the chord surface of the right angle prism is coated with an antireflection coating.

10. The wavelength tuning device of any one of claims 1 to 9, wherein the device has a wavelength tuning accuracy of 0.003 to 0.005 pm.