CN110653488A - A cross-scale high-resolution three-dimensional laser direct writing processing method - Google Patents

Abstract

The invention discloses a cross-scale high-resolution three-dimensional laser direct writing processing method, which comprises the following steps: (1) dividing the processing accuracy grades according to the morphology requirements of different regions of the target structure; (2) selecting corresponding Focus the objective lens and the displacement stage to generate the corresponding processing path; (3) In the laser direct writing process, the polymerization processing is performed according to the target path and the selection of the objective lens; (4) Development and shaping. The invention realizes a cross-scale high-precision micro-machining method on the basis of two-photon polymerization laser direct writing, and takes into account the sub-micron-scale processing accuracy and the centimeter-level overall structure; the focusing objective lens with multiple numerical apertures provides a variety of processing precision. Selected, thus solving the limitation of the focus size of a single focusing objective lens; according to the difference in processing precision between different regions of the target structure, the processing efficiency is further improved, and the target size of the laser direct writing is enlarged.

Description

A cross-scale high-resolution three-dimensional laser direct writing processing method

technical field

The invention relates to a laser direct writing method, in particular to a cross-scale high-resolution three-dimensional laser direct writing processing method.

Background technique

Laser direct writing technology based on two-photon polymerization utilizes the nonlinear optical interaction between femtosecond laser and matter to confine the polymerization reaction to a tiny area of laser focus. The size of the laser focus can be controlled by choosing the wavelength of the laser and the numerical aperture of the focusing objective. Since the induced two-photon polymerization requires the laser energy to reach a certain threshold, adjusting the laser energy and exposure time while determining the size of the laser focus can break through the limitation of the diffraction limit and realize the preparation of microstructures. Using the spatial confinement effect of two-photon polymerization and the relative movement of the laser focus and the target material, the direct writing of complex structures can be realized in three-dimensional space. Therefore, two-photon polymerization can meet high-precision 3D direct writing processing, and has broad application prospects in the fields of micro-nano optical devices, microelectronic systems, microfluidic channels, cell culture scaffolds and other fields.

In the prior art, a high-precision piezoelectric translation stage or a scanning galvanometer system is used to generate the relative motion between the laser focus and the target material. Piezoelectric translation stages and scanning galvanometers can ensure high-quality displacement accuracy, but the processing range of a single processing is usually less than 300 microns. When faced with a larger-scale target structure, it is necessary to use the splicing method to complete the overall processing, which has a long processing cycle and low processing efficiency.

SUMMARY OF THE INVENTION

Purpose of the invention: In order to overcome the deficiencies in the prior art, the purpose of the present invention is to provide a cross-scale high-resolution three-dimensional laser direct writing processing method with high precision and high processing efficiency.

Technical solution: a cross-scale high-resolution three-dimensional laser direct writing processing method described in the present invention comprises the following steps:

(1) In the horizontal and vertical directions, the processing accuracy grades are divided according to the morphology requirements of different areas of the target structure. The size of the target structure in any direction in the three-dimensional space can reach a maximum of 2 cm and a minimum of 100 nanometers. The processing accuracy grades are divided into 100nm, 200nm, 500nm, 1µm, 5µm, 10µm;

(2) Select the corresponding focusing objective lens and displacement stage for the areas with different processing precision. The focusing objective lens is any one of oil immersion objective lens, water immersion objective lens and dry objective lens. The processing area with higher precision requirements selects the larger numerical aperture. The focusing objective lens has a maximum numerical aperture of 1.4. The displacement stage is a combination of a piezoelectric displacement stage and an electronically controlled displacement stage. According to the selection of the focusing objective lens, the corresponding segmentation interval is set to generate the corresponding processing path;

(3) During the laser direct writing process, use the determined focusing objective lens and the generated path file to perform aggregation processing, select the focusing objective lens for different processing areas through the automatic switching device, and adjust the position of the translation stage along the optical axis to make different processing areas. The focal center position of the objective lens is the same;

(4) Development and molding.

Wherein, the focusing objective includes more than 4 objective lenses with different numerical apertures. The objective lenses are arranged in a ring or in a straight line.

Beneficial effect: Compared with the prior art, the present invention has the following remarkable features:

1. Based on two-photon polymerization laser direct writing to realize large-scale and high-precision micro-machining method, taking into account the sub-micron-scale machining accuracy and the centimeter-level overall structure;

2. The use of focusing objective lenses with multiple numerical apertures provides a variety of processing precision options, thus solving the limitation of a single focusing objective lens on the size of the focusing focus;

3. According to the different processing precision between different areas of the target structure, select the appropriate focusing objective lens and moving stage, while having various processing precisions from sub-micron to micron scale, it further improves the processing efficiency and expands the laser direct writing. target size.

Description of drawings

Fig. 1 is the structural representation of the present invention;

Fig. 2 is the first structural representation of the focusing objective lens of the present invention;

Fig. 3 is the second structure schematic diagram of the focusing objective lens of the present invention;

Figure 4 is a flow chart of the present invention.

Detailed ways

As shown in FIG. 1 , the photoresist 1 of the large-scale high-precision laser direct writing processing system is located on the target substrate 2 . The incident laser 7 is focused on any position in the photoresist 1 by the focusing objective lens, and the size of the focused spot can be controlled by the focusing objective lens automatic switching device 6, and the effective aggregate volume and processing accuracy can be controlled by adjusting the laser energy and exposure time at the same time. During the processing, the movement of the piezoelectric translation stage 3 and the large-stroke electronically controlled translation stage 4 makes the laser focus move three-dimensionally relative to the photoresist to form the target structure. The piezoelectric translation stage 3 adopts a three-dimensional piezoelectric translation stage with a stroke of 300 microns and a displacement resolution of 1 nanometer. The large-stroke electronically controlled translation stage 4 is a three-dimensional large-stroke electronically controlled translation stage with a stroke of 25 mm and a displacement resolution of 100 nanometers.

As shown in Figures 2 to 3, during the processing, the control system 5 will control the automatic focusing objective lens switching device 6 to select an appropriate focusing objective lens and a suitable piezoelectric level translation stage 3 according to the size and accuracy requirements of the target area according to Table 1. The focusing objective is one of the following five types: (1) oil lens, magnification 100, numerical aperture 1.4; (2) oil lens, magnification 63, numerical aperture 1.4; (3) air lens, magnification 50, numerical aperture Aperture 0.75; (4) Air mirror, magnification 20, numerical aperture 0.4; (5) Air mirror, magnification 5, numerical aperture 0.1. For processing areas with higher precision requirements, use focusing objectives with larger numerical apertures. The focusing objective lens automatic switching device 6 has 4 (above) objective lens lenses with different numerical apertures, and the lenses are arranged in a ring or in a straight line.

During the laser direct writing process, the focusing objective lens automatic switching device 6 is used to select the designated focusing objective lens for different processing areas, and at the same time adjust the position of the lens so that the focal positions of different focusing objective lenses are the same. The processing path sets the corresponding segmentation interval according to the selection of the focusing objective lens. Table 1 shows the corresponding relationship between the focusing objective lens, the translation stage and the segmentation interval under different target precisions.

Table 1 Comparison table of target accuracy, focusing lens, translation stage and segmentation interval

As shown in Figure 4, the cross-scale high-resolution 3D laser direct writing processing method includes the following steps:

(1) According to the morphology requirements of different regions of the target structure, the machining accuracy grades are divided;

(2) Select the corresponding focusing objective lens and displacement stage for the regions with different machining accuracy, and generate the corresponding machining path;

(3) During the laser direct writing process, the polymerization process is carried out according to the target path and objective lens selection;

(4) After the processing is completed, develop and shape.

Among them, the size of the target structure in any direction in three-dimensional space is up to 2 cm, and the minimum feature size of the fine structure is 100 nanometers.

Claims (8)

1. A cross-scale high-resolution three-dimensional laser direct writing processing method is characterized by comprising the following steps:

(1) dividing machining precision grades in the horizontal direction and the vertical direction according to the precision requirement of the target structure;

(2) selecting corresponding focusing objective lenses and displacement tables for areas with different processing precision to generate corresponding processing paths;

(3) in the laser direct writing processing process, the determined focusing objective lens and the generated path file are utilized for carrying out polymerization processing:

(4) and (5) developing and forming.

2. The three-dimensional laser direct writing processing method according to claim 1, characterized in that: the size of the target structure in any direction in a three-dimensional space reaches 2 cm at most and 100 nm at least, and the processing precision grades are 100 nm, 200 nm, 500 nm, 1 micron, 5 microns and 10 microns.

3. The three-dimensional laser direct writing processing method according to claim 1, characterized in that: the focusing objective lens is any one of an oil immersion objective lens, a water immersion objective lens and a drying objective lens.

4. The three-dimensional laser direct writing processing method according to claim 1, characterized in that: the displacement table is a combination of a piezoelectric displacement table and an electric control displacement table.

5. The three-dimensional laser direct writing processing method according to claim 1, characterized in that: and the processing path sets a corresponding segmentation interval according to the selection of the focusing objective lens.

6. The three-dimensional laser direct writing processing method according to claim 1, characterized in that: in the laser direct writing process, focusing objective lenses are selected for different processing areas through an automatic switching device, and meanwhile, the position of a translation table is adjusted along the optical axis direction, so that the focusing center positions of different objective lenses are the same.

7. The three-dimensional laser direct writing processing method according to claim 1, characterized in that: the focusing objective lens includes 4 or more objective lens.

8. The three-dimensional laser direct writing processing method according to claim 1, characterized in that: the objective lenses are arranged in an annular or linear mode.

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