CN118244589A - Laser direct writing device and laser direct writing method - Google Patents

Abstract

The invention relates to a laser direct writing device and a laser direct writing method, which sequentially comprise a laser, a polarization phase joint modulation module and a scanning direct writing module in the light path propagation direction, wherein the polarization phase joint modulation module sequentially comprises a first half wave plate, a polarization beam splitter prism, a second half wave plate, a vortex wave plate and a spiral phase plate in the light path propagation direction.

Description

Laser direct writing device and laser direct writing method

Technical Field

The invention relates to the field of laser direct writing, in particular to a laser direct writing device and a laser direct writing method.

Background

The laser direct writing technology has the advantages of high precision, high flexibility and the like, is suitable for writing of complex 3D structures, and plays an important role in manufacturing three-dimensional micro-nano optical devices.

In the two-photon laser direct writing photoetching process, a substrate is usually made of high-refractive index materials such as a silicon wafer, and the femtosecond laser is reflected strongly after penetrating through the photoresist and being emitted onto the substrate, and reflected light returns to the inside of the photoresist again. Since the vibration frequency and direction of the reflected light and the incident light are the same, the phase difference is constant, so that the reflected light and the incident light can form a stable interference field (standing wave) in the photoresist, and the light intensity distribution in the photoresist is uneven, so that alternating bright and dark areas are displayed. The bright and dark areas show the intensity of the femtosecond laser, more photochemical polymerization reactions occur in the areas with strong light, and fewer polymerization reactions occur in the areas with weak light intensity, so that the photoresist is longitudinally polymerized in a multi-position exposure mode. The longitudinal multi-position exposure polymerization caused by the standing wave effect can form a remarkable undulating structure on the photoresist profile, and can lead to insufficient strength and adhesiveness of longitudinal exposure lines, and can be randomly shed in the subsequent development process. In conclusion, the existence of standing waves can cause distortion and damage to the three-dimensional micro-nano structure in the writing process.

At present, two methods for inhibiting the standing wave effect exist, the first method is called PEB (post-Exposure Bake), namely, proper baking is carried out after Exposure, and the light intensity distribution is uneven to a certain extent due to the diffusion of the high Wen Cujin photosensitizer, so that a more uniform section can be obtained in the developing process. The method has limited effect and can not solve the problem that the three-dimensional micro-nano structure is damaged caused by the falling of the scribing line. In addition, excessive high temperature baking can damage the three-dimensional micro-nano structure. The second method is to coat an anti-reflection film on the substrate and then coat or drip photoresist on the anti-reflection film, thereby reducing the reflection of light on the substrate. The ideal thickness of the anti-reflection film is one quarter of the wavelength of light, so that the minimization of the intensity of reflected light is realized, therefore, the method has higher requirements on the spin coating precision of the anti-reflection film, has high processing difficulty and improves the cost of laser direct writing processing.

Disclosure of Invention

Based on the above, it is necessary to provide a laser direct writing device and a laser direct writing method for solving the problem of degradation of the quality of the three-dimensional micro-nano structure caused by the standing wave effect.

The laser direct writing device sequentially comprises a laser, a polarization phase joint modulation module and a scanning direct writing module in the light path propagation direction, wherein the polarization phase joint modulation module sequentially comprises a first half wave plate, a polarization beam splitter prism, a second half wave plate, a vortex wave plate and a spiral phase plate in the light path propagation direction.

The polarization phase joint modulation module further comprises a first reflecting mirror positioned between the second half-wave plate and the vortex wave plate.

The scanning direct writing module sequentially comprises a scanning lens, a field lens, an objective lens, a sample stage and a displacement stage in the light path propagation direction.

The scanning direct writing module further comprises a vibrating mirror, the vibrating mirror is positioned between the spiral phase plate and the scanning lens, the displacement table is a piezoelectric displacement table, and the laser direct writing device further comprises a controller, and the vibrating mirror and the displacement table are electrically connected to the controller.

The laser direct writing device further comprises an acousto-optic modulator, and the acousto-optic modulator is electrically connected to the controller.

The scanning direct writing module further comprises a dichroic mirror positioned between the field lens and the objective lens, the laser direct writing device further comprises an imaging module, the imaging module comprises a camera and a third lens, the camera and the third lens are positioned on the side face of the dichroic mirror, and the third lens is positioned between the camera and the dichroic mirror.

The scanning direct writing module further comprises a non-polarized light splitting prism positioned between the dichroic mirror and the objective lens, the laser direct writing device further comprises an illumination module, the illumination module comprises an illumination light source, a fourth lens and a third reflecting mirror, the illumination light source, the fourth lens and the third reflecting mirror are positioned on the side face of the non-polarized light splitting prism, and the illumination light source sequentially passes through the fourth lens and the third reflecting mirror to emit light rays to the non-polarized light splitting prism.

The laser direct writing device further comprises a beam expanding module positioned between the laser and the first half wave plate, wherein the beam expanding module sequentially comprises a first lens and a second lens in the light path propagation direction, and a small hole is arranged between the first lens and the second lens.

The laser direct writing device further comprises a second reflecting mirror positioned between the second lens and the first half-wave plate.

A laser direct writing method comprising:

Purifying the polarization state of laser emitted by the laser by using a first half-wave plate and a polarization beam splitter prism;

Changing the polarization angle of the purified laser light by using a second half-wave plate;

the laser with the changed polarization angle sequentially passes through the vortex wave plate and the spiral phase plate to obtain angular polarization vortex rotation.

The angular polarization vortex rotation sequentially passes through a galvanometer, a scanning lens, a field lens, a dichroic mirror, a non-polarized beam splitter prism and an objective lens, then focuses on photoresist on the surface of a sample stage, and realizes three-dimensional inscription by controlling an acousto-optic modulator, the galvanometer and a displacement stage;

The light emitted by the illumination light source illuminates the sample surface, and the camera observes the energy distribution condition in the focal plane of the objective lens, monitors the laser direct writing process and observes the writing result.

The beneficial effects of the invention are as follows:

according to the invention, through the vector light field composite regulation and control of polarization combined phase, by utilizing the topological charge reversal characteristic of angular polarization vortex rotation in the reflection process, a super diffraction limit focusing light spot without a longitudinal standing wave effect is formed near a focal plane, so that the influence of the standing wave effect is avoided when a three-dimensional structure is processed on a photoresist, and the deviation between an actual inscription structure and a design structure is reduced.

The polarization phase joint modulation module has stable light path and is easy to migrate.

Compared with the traditional PEB mode, the laser direct writing device for processing the three-dimensional micro-nano structure has the advantages that the standing wave effect is restrained more effectively and controllably, and the processed micro-nano structure is not affected. Compared with the anti-reflection coating mode, the cost is lower, and the processing mode is simpler.

Drawings

FIG. 1 is a schematic plan view of a laser direct writing device according to an embodiment 1 of the present invention;

FIG. 2 is a polarization distribution diagram of incident light at the entrance pupil of the objective lens in example 1 of the present invention;

FIG. 3 is a graph showing the energy distribution in the longitudinal yz plane near the focal point of the angularly polarized vortex light focused by the objective lens according to example 1 of the present invention;

FIG. 4 is a graph showing the energy distribution in the xy plane transverse to the focal plane of the angular polarized vortex light after it has been focused by the objective lens in example 1 of the present invention;

Fig. 5 is an energy distribution diagram in the longitudinal yz plane in the vicinity of the focal point after the laser light passes through the objective lens in comparative example 1 of the present invention.

Reference numerals:

1. A laser; 21. a first lens; 22. a small hole; 23. a second lens; 31. a first half-wave plate; 32. a polarization beam splitter prism; 33. a second half-wave plate; 34. a first mirror; 35. a vortex wave plate; 36. a spiral phase plate; 41. vibrating mirror; 42. a scanning lens; 43. a field lens; 44. a dichroic mirror; 45. a non-polarizing beam-splitting prism; 46. an objective lens; 47. a sample stage; 48. a displacement table; 5. an acousto-optic modulator; 6. a second mirror; 71. a camera; 72. a third lens; 81. an illumination light source; 82. a fourth lens; 83. and a third mirror.

Detailed Description

In order that the above objects, features and advantages of the invention will be readily understood, a more particular description of the invention will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit of the invention, whereby the invention is not limited to the specific embodiments disclosed below.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present invention, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

It will be understood that when an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like are used herein for illustrative purposes only and are not meant to be the only embodiment.

Example 1:

Referring to fig. 1, the present embodiment provides a laser direct writing device, which sequentially includes a laser 1, an acousto-optic modulator 5, a beam expanding module, a polarization phase joint modulation module, and a scanning direct writing module in the light path propagation direction. The laser direct writing device further comprises a controller.

The laser light emitted by the laser 1 in this embodiment is a femtosecond laser, and the duration of a single pulse is about 200fs, so as to provide a necessary condition for nonlinear two-photon absorption of the photoresist. The acousto-optic modulator 5 is electrically connected to the controller, and outputs a corresponding voltage through the controller so as to control and adjust the average power of the laser 1 input into the main light path. Accordingly, the wavelength of light emitted by the laser 1 matches the operating wavelength of the acousto-optic modulator 5. The laser 1 and the acousto-optic modulator 5 together form a laser output module.

The scanning direct writing module at least comprises an objective lens 46 and a sample stage 47, and the main function of the beam expanding module is to optimize the spot mode of the femtosecond laser and enlarge the spot diameter, so that the laser spot can fully cover the entrance pupil surface of the lens 46 finally, the full utilization of the numerical aperture of the objective lens 46 is realized, and then the photoresist on the sample stage 47 is subjected to exposure polymerization. After the laser is optimized by the beam expanding module, the laser can enter the scanning direct writing module only through the modulation function of the polarization phase joint modulation module.

The polarization phase joint modulation module comprises a first half-wave plate 31, a polarization splitting prism 32, a second half-wave plate 33, a vortex wave plate 35 and a spiral phase plate 36, wherein the first half-wave plate 31, the polarization splitting prism 32, the second half-wave plate 33, the vortex wave plate 35 and the spiral phase plate 36 are sequentially arranged in the light path propagation direction. The first half-wave plate 31, the second half-wave plate 33, the vortex wave plate 35, and the spiral phase plate 36 are each mounted on a rotatable optical frame so as to rotate about respective corresponding optical axes.

The first half-wave plate 31 can adjust the polarization angle of the incident laser light by rotating about its own optical axis. And then the laser irradiates the polarization beam splitter prism 32, the vertical polarization component in the laser is reflected by the polarization beam splitter prism 32, and the horizontal polarization component in the laser transmits the polarization beam splitter prism 32, so that the purposes of purifying the polarization state in the laser and adjusting the laser intensity can be realized under the cooperation of the first half wave plate 31 and the polarization beam splitter prism 32, and the follow-up polarization control is facilitated.

The laser light passes through the polarization splitting prism 32 and then changes its polarization angle again under the action of the second half-wave plate 33, so that it can cooperate with the vortex wave plate 35 to generate an angular polarization vector laser light. The generated angularly polarized vector laser is subjected to vortex phase by the spiral phase plate 36, and finally, the angularly polarized vortex rotation is formed. The angularly polarized vortex light is eventually focused by objective lens 46 onto the photoresist on sample stage 47, causing polymerization at the corresponding locations on the photoresist.

Preferably, the polarization phase joint modulation module further comprises a first reflecting mirror 34 located between the second half-wave plate 33 and the vortex wave plate 35, the laser irradiates the first reflecting mirror 34 after changing the polarization angle through the second half-wave plate 33, and then is reflected to the vortex wave plate 35 through the first reflecting mirror 34, so that the light path propagation direction and the space arrangement mode of the polarization phase joint modulation module are optimized, and the space size additionally occupied by the polarization phase joint modulation module is reduced.

The beam expanding module is in particular located between the laser 1 and the first half-wave plate 31. The beam expanding module in this embodiment includes a first lens 21 and a second lens 23, where the first lens 21 and the second lens 23 are sequentially disposed in the optical path propagation direction, and an aperture 22 is disposed between the first lens 21 and the second lens 23. The laser light emitted from the laser 1 is directed to the first half wave plate 31 through the first lens 21, the aperture 22 and the second lens 23 in this order. Wherein the aperture 22 can perform a spatial filtering function, and the beam expansion module optimizes the spot pattern by diffraction of the aperture 22. The first lens 21 and the second lens 23 can be matched to realize the amplification of the diameter of the light spot, and the amplification factor is the ratio of the focal length of the second lens 23 to the focal length of the first lens 21. In this embodiment, the aperture 22 is disposed between the first lens 21 and the second lens 23, so that the beam expanding module has the effect of optimizing the spot mode and the diameter of the amplified spot.

Preferably, the laser direct writing device further comprises a second mirror 6 between the second lens 23 and the first half-wave plate 31. The laser emitted by the second lens 23 is reflected to the first half-wave plate 31 through the second reflecting mirror 6, and under the cooperation of the second reflecting mirror 6 and the first reflecting mirror 34, the structural symmetry of the whole laser direct writing device is improved.

The scanning direct writing module further includes a galvanometer 41, a scanning lens 42, a field lens 43, and a displacement stage 48, the scanning lens 42, the field lens 43, an objective lens 46, a sample stage 47, and the displacement stage 48 being sequentially arranged in the optical path propagation direction. The sample stage 47 is placed on the displacement stage 48, the controller controls the acousto-optic modulator 5 to switch and the galvanometer 41 to rotate, and the displacement stage 48 controls the movement of the sample stage 47, so as to change the laser energy at the focus of the objective lens 46 and the relative position between the focus and the photoresist on the sample stage 47, and change the position of the photoresist where polymerization reaction occurs, so that three-dimensional scanning direct writing lithography is realized.

Galvanometer 41 is positioned between spiral phase plate 36 and scan lens 42, while displacement stage 48 is a piezoelectric displacement stage, with galvanometer 41 and displacement stage 48 both electrically connected to the controller. The scanning flow is as follows: scanning is carried out by the vibrating mirror 41, then the displacement table 48 transversely moves to the next position, and scanning is carried out by the vibrating mirror 41; after writing on one plane is completed, displacement table 48 is moved longitudinally to the next position and the above described writing process is repeated.

In order to facilitate focusing and observation of writing results, the laser direct writing device further comprises an imaging module. In particular, in the present embodiment, the imaging module includes the camera 71 and the third lens 72, and the scanning direct writing module further includes the dichroic mirror 44, and the dichroic mirror 44 is located between the field lens 43 and the objective lens 46, and the field lens 43, the dichroic mirror 44, and the objective lens 46 are sequentially arranged along a straight line. The camera 71 and the third lens 72 are not disposed on a straight line where the field lens 43, the dichroic mirror 44, and the objective lens 46 are located, but are located on a side of the dichroic mirror 44, with the third lens 72 being located between the camera 71 and the dichroic mirror 44. Of course, the operating wavelength of dichroic mirror 44 also needs to match the emission wavelength of laser 1. After the light irradiates the sample stage 47, the reflected light passes through the dichroic mirror 44, and is reflected by the dichroic mirror 44, and forms an image at the camera 71 through the converging action of the third lens 72, so that observation is performed.

Preferably, the laser direct writing device further comprises an illumination module, and the illumination module is used for providing light different from the working wavelength of the laser 1 to illuminate the processing area, so as to monitor the writing process and image the writing result. Specifically, the illumination module includes an illumination light source 81, a fourth lens 82, and a third mirror 83, and the scanning direct writing module further includes an unpolarized beam splitter prism 45 located between the dichroic mirror 44 and the objective lens 46, the unpolarized beam splitter prism 45 being located on a straight line where the dichroic mirror 44 and the objective lens 46 are located. The illumination light source 81, the fourth lens 82, and the third mirror 83 are also not disposed on the straight line where the dichroic mirror 44 and the objective 46 are located, but are located on the side of the unpolarized dichroic prism 45. The light beam emitted from the illumination light source 81 is collimated by the fourth lens 82, and then is directed to the third reflecting mirror 83, and then is reflected by the third reflecting mirror 83 to the non-polarizing beam splitter prism 45, and the non-polarizing beam splitter prism 45 then reflects the light beam to the objective lens 46, and is directed to the displacement stage 48. The light is reflected by the displacement stage 48 and is redirected by the objective lens 46 and the non-polarizing beam splitter prism 45 to the dichroic mirror 44, and finally reaches the camera 71, so that the energy distribution of the angular polarized eddy current in the focal plane of the objective lens 46 can be more easily observed, and the laser direct writing process can be monitored.

Wherein the third mirror 83 enables a more rational spatial distribution between the illumination module and the scanning direct writing module, reducing the space additionally occupied by the illumination module.

Correspondingly, the embodiment also provides a laser direct writing method, which is based on the laser direct writing device, and the laser direct writing method sequentially comprises the following steps:

Step 101: the laser emitted by the laser 1 sequentially passes through the first lens 21, the small hole 22 and the second lens 23 to perform spot mode optimization and spot diameter amplification, and then irradiates to the second reflecting mirror 6, and irradiates to the first half wave plate 31 under the reflecting action of the second reflecting mirror 6, and then is emitted to the polarization splitting prism 32 from the first half wave plate 31, and the polarization state of the laser is purified by the first half wave plate 31 and the polarization splitting prism 32;

step 102: the laser light emitted from the polarization splitting prism 32 is emitted to the second half-wave plate 33, and the polarization angle of the laser light is changed by the second half-wave plate 33;

Step 103: the laser emitted from the second half wave plate 33 is emitted to the first reflecting mirror 34, then reflected to the vortex wave plate 35 by the first reflecting mirror 34, and then emitted to the spiral phase plate 36 from the vortex wave plate 35, so as to sequentially obtain angular polarization vortex rotation;

Step 104: the angular polarization vortex rotation is focused on the photoresist on the sample stage 47 through the galvanometer 41, the scanning lens 42, the field lens 43, the dichroic mirror 44, the non-polarization beam splitter prism 45 and the objective lens 46 in sequence, and the acousto-optic modulator 5, the galvanometer 41 and the displacement stage 48 are controlled so as to realize three-dimensional inscription;

Wherein the Jones matrix of the polarization of the incident laser light at objective 46 may be represented in a Cartesian coordinate system as After refraction by objective lens 46, its electric field |E _∞ > can be expressed as: wherein E _inc represents the complex amplitude of the incident laser light, n _θ and/> Is a unit vector in a spherical coordinate system, theta is a divergence angle,/>For angular coordinates, n ₁ and n ₂ are the refractive indices of the two media before and after focusing. Since a portion of objective lens 46 is immersed in the photoresist, n ₁ is the refractive index of the photoresist, specifically 1.518 in this embodiment, and n ₂ is the refractive index of the silicon substrate, specifically 3.88.

Wherein,

In combination with the above definition, the angular spectrum of electric field |E _∞ > after refraction by objective lens 46 is expressed in terms of:

wherein k _x,k_y and k _z respectively represent spatial frequencies in three directions while satisfying And k _z = kcos θ, k being the wave vector of the laser in the medium.

In combination with the tight focus vector diffraction integration formula, it can be deduced that the electric field near the focal plane after focusing by the high numerical aperture objective lens 46:

Where f is the focal length of the objective lens.

By introducing a generalized fresnel coefficient, the form of the electric field after reflection by the sample stage 47:

Wherein,

Where (r ^p,r^s) is the generalized fresnel coefficient, which is related to the permittivity and permeability of the substrate medium, z ₀ is the distance between the focal plane (actual writing surface) and the sample stage 47 (reflecting surface). Therefore, we can obtain a standing wave field formed by interference of the incident laser and the reflected laser: i E _f(x,y,z)>+|E_r (x, y, z) >.

In this embodiment, the numerical aperture na=1.45 of the objective lens 46, and the refractive index n ₁ =1.518. The incident light at objective 46 is Gaussian and angularly polarized with a Jones matrix ofThe polarization distribution in the transverse xy plane is shown in fig. 2 (the vortex phase distribution of topological charge m=1).

On the basis, three positions are selected from the photoresist to simulate the energy distribution of the femtosecond laser near the focal plane, and the simulation result is shown in fig. 3. In which fig. 3 (a) corresponds to the case where the sample plane (the distance between the sample plane and the sample stage 47 is always fixed) and the focal plane coincide, that is, the distance is 0, fig. 3 (b) corresponds to the case where the distance between the sample plane and the focal plane is 0.5 times the wavelength, and fig. 3 (c) corresponds to the case where the distance between the sample plane and the focal plane is 2 times the wavelength, it is not difficult to find that the laser energy is distributed in gaussian as a whole, and no significant light-dark alternation occurs, thereby proving that the standing wave effect near the focal plane is effectively suppressed in this embodiment.

Referring to fig. 4, where fig. 4 (a) corresponds to the case where the sample plane and the focal plane coincide, fig. 4 (b) corresponds to the case where the sample plane and the focal plane are separated by 0.5 times the wavelength, and fig. 4 (c) corresponds to the case where the sample plane and the focal plane are separated by 2 times the wavelength, the angular polarization vortex rotation exhibits a solid distribution in the entire lateral direction of the energy distribution, which proves to be suitable for laser direct writing.

Step 105: the light emitted from the illumination light source 81 is sequentially irradiated to the unpolarized beam splitter prism 45 through the collimation of the fourth lens 82 and the reflection of the third mirror 83, then the light is reflected to the objective lens 46 by the unpolarized beam splitter prism 45, then irradiated to the displacement table 48 for reflection, the reflected light sequentially passes through the objective lens 46 and the unpolarized beam splitter prism 45 to reach the dichroic mirror 44 and is reflected by the dichroic mirror 44, then reaches the camera 71 under the focusing action of the third lens 72, and the energy distribution condition in the focal plane of the objective lens 46, the monitoring laser direct writing process and the observation writing result are observed by the camera 71.

Comparative examples:

The present comparative embodiment differs from embodiment 1 in that the polarization phase joint modulation module is removed, i.e., no amplitude phase polarization modulation is applied.

Referring to fig. 5, where fig. 5 (a) corresponds to the case where the sample plane and the focal plane coincide, fig. 5 (b) corresponds to the case where the sample plane and the focal plane are separated by 0.5 times the wavelength, and fig. 5 (c) corresponds to the case where the sample plane and the focal plane are separated by 2 times the wavelength, it is not difficult to find that there is a strong or weak energy distribution in the light transmission direction, that is, a standing wave is generated, resulting in the case where the three-dimensional structure of laser direct writing has delamination and is inconsistent with the design.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples illustrate only a few embodiments of the invention, which are described in detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

Claims (10)

1. The laser direct writing device is characterized by sequentially comprising a laser (1), a polarization phase joint modulation module and a scanning direct writing module in the light path propagation direction, wherein the polarization phase joint modulation module sequentially comprises a first half wave plate (31), a polarization beam splitting prism (32), a second half wave plate (33), a vortex wave plate (35) and a spiral phase plate (36) in the light path propagation direction.

2. The laser direct write device according to claim 1, characterized in that the polarization phase joint modulation module further comprises a first mirror (34) between the second half-wave plate (33) and the vortex wave plate (35).

3. The laser direct writing device according to claim 1, wherein the scanning direct writing module comprises, in order in the optical path propagation direction, a scanning lens (42), a field lens (43), an objective lens (46), a sample stage (47), and a displacement stage (48).

4. A laser direct writing device according to claim 3, characterized in that the scanning direct writing module further comprises a galvanometer (41), the galvanometer (41) being located between the spiral phase plate (36) and the scanning lens (42), the displacement stage (48) being a piezo-electric displacement stage, the laser direct writing device further comprising a controller, both the galvanometer (41) and the displacement stage (48) being electrically connected to the controller.

5. The laser direct write device according to claim 4, characterized in that the laser direct write device further comprises an acousto-optic modulator (5), the acousto-optic modulator (5) being electrically connected to the controller.

6. A laser direct writing device according to claim 3, characterized in that the scanning direct writing module further comprises a dichroic mirror (44) between the field lens (43) and the objective lens (46), the laser direct writing device further comprises an imaging module comprising a camera (71) and a third lens (72), the camera (71) and the third lens (72) being located at the side of the dichroic mirror (44), and the third lens (72) being located between the camera (71) and the dichroic mirror (44).

7. The laser direct writing device according to claim 6, wherein the scanning direct writing module further comprises a non-polarizing beam splitter prism (45) located between the dichroic mirror (44) and the objective lens (46), the laser direct writing device further comprises an illumination module comprising an illumination light source (81), a fourth lens (82) and a third mirror (83), the illumination light source (81), the fourth lens (82) and the third mirror (83) are located at the side of the non-polarizing beam splitter prism (45), and the illumination light source (81) directs light to the non-polarizing beam splitter prism (45) sequentially through the fourth lens (82) and the third mirror (83).

8. The laser direct writing device according to claim 1, characterized in that it further comprises a beam expansion module located between the laser (1) and the first half-wave plate (31), the beam expansion module comprising, in order in the direction of propagation of the optical path, a first lens (21) and a second lens (23), an aperture (22) being provided between the first lens (21) and the second lens (23).

9. The laser direct write device according to claim 8, characterized in that it further comprises a second mirror (6) between the second lens (23) and the first half-wave plate (31).

10. A laser direct writing method, comprising:

Purifying the polarization state of laser light emitted by the laser (1) by using a first half-wave plate (31) and a polarization beam splitter prism (32);

changing the polarization angle of the purified laser light using a second half-wave plate (33);

Allowing the laser light with the changed polarization angle to sequentially pass through a vortex wave plate (35) and a spiral phase plate (36) to obtain angular polarization vortex rotation;

The angular polarization vortex rotation sequentially passes through a galvanometer (41), a scanning lens (42), a field lens (43), a dichroic mirror (44), a non-polarized beam-splitting prism (45) and an objective lens (46), and then focuses on photoresist on the surface of a sample stage (47), and three-dimensional inscription is realized by controlling an acousto-optic modulator (5), the galvanometer (41) and a displacement stage (48);

The light emitted by the illumination light source (81) illuminates the sample surface, and the camera (71) observes the energy distribution in the focal plane of the objective lens (46), monitors the laser direct writing process and observes the writing result.